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Nguyen DK, Nguyen TP, Li YR, Ohme-Takagi M, Liu ZH, Ly TT, Nguyen VA, Trinh NN, Huang HJ. Comparative study of two indoor microbial volatile pollutants, 2-Methyl-1-butanol and 3-Methyl-1-butanol, on growth and antioxidant system of rice (Oryza sativa) seedlings. Ecotoxicol Environ Saf 2024; 272:116055. [PMID: 38340597 DOI: 10.1016/j.ecoenv.2024.116055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 01/24/2024] [Accepted: 01/28/2024] [Indexed: 02/12/2024]
Abstract
2-Methyl-1-butanol (2MB) and 3-Methyl-1-butanol (3MB) are microbial volatile organic compounds (VOCs) and found in indoor air. Here, we applied rice as a bioindicator to investigate the effects of these indoor microbial volatile pollutants. A remarkable decrease in germination percentage, shoot and root elongation, as well as lateral root numbers were observed in 3MB. Furthermore, ROS production increased by 2MB and 3MB, suggesting that pentanol isomers could induce cytotoxicity in rice seedlings. The enhancement of peroxidase (POD) and catalase (CAT) activity provided evidence that pentanol isomers activated the enzymatic antioxidant scavenging systems, with a more significant effect observed in 3MB. Furthermore, 3MB induced higher activity levels of glutathione (GSH), oxidized glutathione (GSSG), and the GSH/GSSG ratio in rice compared to the levels induced by 2MB. Additionally, qRT-PCR analysis showed more up-regulation in the expression of glutaredoxins (GRXs), peroxiredoxins (PRXs), thioredoxins (TRXs), and glutathione S-transferases (GSTUs) genes in 3MB. Taking the impacts of pentanol isomers together, the present study suggests that 3MB exhibits more cytotoxic than 2MB, as such has critical effects on germination and the early seedling stage of rice. Our results provide molecular insights into how isomeric indoor microbial volatile pollutants affect plant growth through airborne signals.
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Affiliation(s)
- Diem-Kieu Nguyen
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Tri-Phuong Nguyen
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Yi-Rong Li
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Masaru Ohme-Takagi
- Institute of Tropical Plant Sciences and Microbiology, National Cheng Kung University, Tainan, Taiwan
| | - Zin-Huang Liu
- Graduate Program in Translational Agricultural Sciences, NCKU and Academia Sinica, Taiwan
| | - Thach-Thao Ly
- Graduate Program in Translational Agricultural Sciences, NCKU and Academia Sinica, Taiwan
| | - Van-Anh Nguyen
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan; Intellectual Property Office of Vietnam, Thanh Xuan District, Ha Noi, Vietnam
| | - Ngoc-Nam Trinh
- Industrial University of Ho Chi Minh City, Go Vap District, Ho Chi Minh, Vietnam
| | - Hao-Jen Huang
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan; Institute of Tropical Plant Sciences and Microbiology, National Cheng Kung University, Tainan, Taiwan; Graduate Program in Translational Agricultural Sciences, NCKU and Academia Sinica, Taiwan.
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Yang W, Wu T, Tu S, Qin Y, Shen C, Li J, Choi MK, Duan F, Zhang Y. Redundant neural circuits regulate olfactory integration. PLoS Genet 2022; 18:e1010029. [PMID: 35100258 PMCID: PMC8830790 DOI: 10.1371/journal.pgen.1010029] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 02/10/2022] [Accepted: 01/11/2022] [Indexed: 11/18/2022] Open
Abstract
Olfactory integration is important for survival in a natural habitat. However, how the nervous system processes signals of two odorants present simultaneously to generate a coherent behavioral response is poorly understood. Here, we characterize circuit basis for a form of olfactory integration in Caenorhabditis elegans. We find that the presence of a repulsive odorant, 2-nonanone, that signals threat strongly blocks the attraction of other odorants, such as isoamyl alcohol (IAA) or benzaldehyde, that signal food. Using a forward genetic screen, we found that genes known to regulate the structure and function of sensory neurons, osm-5 and osm-1, played a critical role in the integration process. Loss of these genes mildly reduces the response to the repellent 2-nonanone and disrupts the integration effect. Restoring the function of OSM-5 in either AWB or ASH, two sensory neurons known to mediate 2-nonanone-evoked avoidance, is sufficient to rescue. Sensory neurons AWB and downstream interneurons AVA, AIB, RIM that play critical roles in olfactory sensorimotor response are able to process signals generated by 2-nonanone or IAA or the mixture of the two odorants and contribute to the integration. Thus, our results identify redundant neural circuits that regulate the robust effect of a repulsive odorant to block responses to attractive odorants and uncover the neuronal and cellular basis for this complex olfactory task. In their natural environment, animals, including humans, encounter complex olfactory stimuli. Thus, how the brain processes multiple sensory cues to generate a coherent behavioral output is critical for the survival of the animal. In the present study, we combined molecular cellular genetics, optical physiology and behavioral analysis to study a common olfactory phenomenon in which the presence of one odorant blocks the response to another. Our results show that the integrated response is regulated by redundant neuronal circuits that engage several interneurons essential for olfactory sensorimotor responses, a mechanism that likely ensures a robust behavioral response to sensory cues representing information critical for survival.
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Affiliation(s)
- Wenxing Yang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
- * E-mail: (WY); (YZ)
| | - Taihong Wu
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Shasha Tu
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Yuang Qin
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Chengchen Shen
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Jiangyun Li
- Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Myung-Kyu Choi
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Fengyun Duan
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
- * E-mail: (WY); (YZ)
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Abstract
The soil bacterium Streptomyces pactum ATCC 27456 produces a number of polyketide natural products. Among them is NFAT-133, an inhibitor of the nuclear factor of activated T cells (NFAT) that suppresses interleukin-2 (IL-2) expression and T cell proliferation. Biosynthetic gene inactivation in the ATCC 27456 strain revealed the ability of this strain to produce other polyketide compounds including analogues of NFAT-133. Consequently, seven new derivatives of NFAT-133, TM-129-TM-135, together with a known compound, panowamycin A, were isolated from the culture broth of S. pactum ATCC 27456 ΔptmTDQ. Their chemical structures were elucidated on the basis of their HRESIMS, 1D and 2D NMR spectroscopy, and ECD calculation and spectral data. NFAT-133, TM-132, TM-135, and panowamycin A showed no antibacterial activity or cytotoxicity, but weakly reduced the production of LPS-induced nitric oxide in RAW264.7 cells in a dose-dependent manner. A revised chemical structure of panowamycin A and proposed modes of formation of the new NFAT-133 analogues are also presented.
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Affiliation(s)
- Wei Zhou
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, OR 97331, United States
| | - Priyapan Posri
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, OR 97331, United States
| | - Xiao-Jing Liu
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, People’s Republic of China
| | - Zhiran Ju
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, OR 97331, United States
| | - Wen-Jian Lan
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, People’s Republic of China
| | - Taifo Mahmud
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, OR 97331, United States
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Neiers F, Jarriault D, Menetrier F, Faure P, Briand L, Heydel JM. The odorant metabolizing enzyme UGT2A1: Immunolocalization and impact of the modulation of its activity on the olfactory response. PLoS One 2021; 16:e0249029. [PMID: 33765098 PMCID: PMC7993815 DOI: 10.1371/journal.pone.0249029] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 03/09/2021] [Indexed: 02/06/2023] Open
Abstract
Odorant metabolizing enzymes (OMEs) are expressed in the olfactory epithelium (OE) where they play a significant role in the peripheral olfactory process by catalyzing the fast biotransformation of odorants leading either to their elimination or to the synthesis of new odorant stimuli. The large family of OMEs gathers different classes which interact with a myriad of odorants alike and complementary to olfactory receptors. Thus, it is necessary to increase our knowledge on OMEs to better understand their function in the physiological process of olfaction. This study focused on a major olfactory UDP-glucuronosyltransferase (UGT): UGT2A1. Immunohistochemistry and immunogold electronic microscopy allowed to localize its expression in the apical part of the sustentacular cells and originally at the plasma membrane of the olfactory cilia of the olfactory sensory neurons, both locations in close vicinity with olfactory receptors. Moreover, using electroolfactogram, we showed that a treatment of the OE with beta-glucuronidase, an enzyme which counterbalance the UGTs activity, increased the response to eugenol which is a strong odorant UGT substrate. Altogether, the results supported the function of the olfactory UGTs in the vertebrate olfactory perireceptor process.
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Affiliation(s)
- Fabrice Neiers
- Centre des Sciences du Goût et de l’Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, Dijon, France
| | - David Jarriault
- Centre des Sciences du Goût et de l’Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, Dijon, France
| | - Franck Menetrier
- Centre des Sciences du Goût et de l’Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, Dijon, France
| | - Philippe Faure
- Centre des Sciences du Goût et de l’Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, Dijon, France
| | - Loïc Briand
- Centre des Sciences du Goût et de l’Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, Dijon, France
| | - Jean-Marie Heydel
- Centre des Sciences du Goût et de l’Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, Dijon, France
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Di Francesco A, Zajc J, Gunde-Cimerman N, Aprea E, Gasperi F, Placì N, Caruso F, Baraldi E. Bioactivity of volatile organic compounds by Aureobasidium species against gray mold of tomato and table grape. World J Microbiol Biotechnol 2020; 36:171. [PMID: 33067644 PMCID: PMC7567711 DOI: 10.1007/s11274-020-02947-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 10/08/2020] [Indexed: 11/24/2022]
Abstract
Aureobasidium strains isolated from diverse unconventional environments belonging to the species A. pullulans, A. melanogenum, and A. subglaciale were evaluated for Volatile Organic Compounds (VOCs) production as a part of their modes of action against Botrytis cinerea of tomato and table grape. By in vitro assay, VOCs generated by the antagonists belonging to the species A. subglaciale showed the highest inhibition percentage of the pathogen mycelial growth (65.4%). In vivo tests were conducted with tomatoes and grapes artificially inoculated with B. cinerea conidial suspension, and exposed to VOCs emitted by the most efficient antagonists of each species (AP1, AM10, AS14) showing that VOCs of AP1 (A. pullulans) reduced the incidence by 67%, partially confirmed by the in vitro results. Conversely, on table grape, VOCs produced by all the strains did not control the fungal incidence but were only reducing the infection severity (< 44.4% by A. pullulans; < 30.5% by A. melanogenum, and A. subglaciale). Solid-phase microextraction (SPME) and subsequent gas chromatography coupled to mass spectrometry identified ethanol, 3-methyl-1-butanol, 2-methyl-1-propanol as the most produced VOCs. However, there were differences in the amounts of produced VOCs as well as in their repertoire. The EC50 values of VOCs for reduction of mycelial growth of B. cinerea uncovered 3-methyl-1-butanol as the most effective compound. The study demonstrated that the production and the efficacy of VOCs by Aureobasidium could be directly related to the specific species and pathosystem and uncovers new possibilities for searching more efficient VOCs producing strains in unconventional habitats other than plants.
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Affiliation(s)
- A Di Francesco
- CRIOF-Department of Agricultural Sciences, University of Bologna, Via Gandolfi, 19, 40057, Cadriano, Bologna, Italy.
- Department of Agricultural and Food Sciences, University of Bologna, Viale Fanin, 42, 40127, Bologna, Italy.
| | - J Zajc
- Plant Protection Department, Agricultural Institute of Slovenia, Hacquetova ulica 17, 1000, Ljubljana, Slovenia
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
| | - N Gunde-Cimerman
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
| | - E Aprea
- Center Agriculture Food Environment, University of Trento/Fondazione Edmund Mach, 38010, San Michele all'Adige, TN, Italy
- Research and Innovation Centre, Fondazione Edmund Mach, via Mach 1, 38010, San Michele all' Adige, Trento, Italy
| | - F Gasperi
- Center Agriculture Food Environment, University of Trento/Fondazione Edmund Mach, 38010, San Michele all'Adige, TN, Italy
- Research and Innovation Centre, Fondazione Edmund Mach, via Mach 1, 38010, San Michele all' Adige, Trento, Italy
| | - N Placì
- Department of Agricultural and Food Sciences, University of Bologna, Viale Fanin, 42, 40127, Bologna, Italy
| | - F Caruso
- Department of Agricultural and Food Sciences, University of Bologna, Viale Fanin, 42, 40127, Bologna, Italy
| | - E Baraldi
- CRIOF-Department of Agricultural Sciences, University of Bologna, Via Gandolfi, 19, 40057, Cadriano, Bologna, Italy
- Department of Agricultural and Food Sciences, University of Bologna, Viale Fanin, 42, 40127, Bologna, Italy
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6
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Miazzi F, Hoyer C, Sachse S, Knaden M, Wicher D, Hansson BS, Lavista-Llanos S. Optimization of Insect Odorant Receptor Trafficking and Functional Expression Via Transient Transfection in HEK293 Cells. Chem Senses 2019; 44:673-682. [PMID: 31504297 PMCID: PMC6821309 DOI: 10.1093/chemse/bjz062] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Insect odorant receptors (ORs) show a limited functional expression in various heterologous expression systems including insect and mammalian cells. This may be in part due to the absence of key components driving the release of these proteins from the endoplasmic reticulum and directing them to the plasma membrane. In order to mitigate this problem, we took advantage of small export signals within the human HCN1 and Rhodopsin that have been shown to promote protein release from the endoplasmic reticulum and the trafficking of post-Golgi vesicles, respectively. Moreover, we designed a new vector based on a bidirectional expression cassette to drive the functional expression of the insect odorant receptor coreceptor (Orco) and an odor-binding OR, simultaneously. We show that this new method can be used to reliably express insect ORs in HEK293 cells via transient transfection and that is highly suitable for downstream applications using automated and high-throughput imaging platforms.
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Affiliation(s)
- Fabio Miazzi
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Carolin Hoyer
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Silke Sachse
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Markus Knaden
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Dieter Wicher
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Bill S Hansson
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Sofia Lavista-Llanos
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
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Molander MA, Winde IB, Burman J, Nyabuga FN, Lindblom TUT, Hanks LM, Millar JG, Larsson MC. Common Cerambycid Pheromone Components as Attractants for Longhorn Beetles (Cerambycidae) Breeding in Ephemeral Oak Substrates in Northern Europe. J Chem Ecol 2019; 45:537-548. [PMID: 31254146 PMCID: PMC6661259 DOI: 10.1007/s10886-019-01082-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/31/2019] [Accepted: 06/12/2019] [Indexed: 11/26/2022]
Abstract
Longhorn beetles are ecologically important insects in forest ecosystems as decomposers of woody substrates, microhabitat engineers, and as components of forest food webs. These species can be greatly affected both positively and negatively by modern forestry management practices, and should be monitored accordingly. Through headspace sampling, coupled gas chromatography-electroantennography, gas chromatography-mass spectrometry, and field bioassays, we identified two compounds, 2-methyl-1-butanol and 3-hydroxy-2-hexanone, that constitute aggregation-sex pheromone attractants of three cerambycid species which breed primarily in different types of fresh, recently dead oak wood in Northern Europe: Pyrrhidium sanguineum (L.), Phymatodes alni ssp. alni (L.), and Phymatodes testaceus (L.) (Cerambycinae: Callidiini). Analyses of headspace volatiles collected from live insects indicated that the male-produced aggregation-sex pheromone of P. sanguineum is a 1–15:100 blend of (R)-2-methyl-1-butanol and (R)-3-hydroxy-2-hexanone, whereas the corresponding ratios for P. alni were 70–110:100. In field bioassays, adult P. sanguineum and P. alni were significantly attracted to multiple blends with varying ratios of the two compounds. When tested individually, the compounds were minimally attractive. In contrast, adult P. testaceus exhibited nonspecific attraction to both of the individual compounds and to different blends, despite the hydroxyketone not being part of its pheromone, which consists of (R)-2-methyl-1-butanol alone. Overall, our results suggest that a blend of 50:100 of racemic 2-methyl-1-butanol and 3-hydroxy-2-hexanone is appropriate for parallel, cost-efficient pheromone-based monitoring of all three species. In particular, these species could serve as useful indicators of how modern forestry practices affect a whole guild of saproxylic insects that require ephemeral deadwood substrates for successful breeding.
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Affiliation(s)
- Mikael A Molander
- Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, Sundsvägen 14, 230 53, Alnarp, Sweden.
| | - Inis B Winde
- Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, Sundsvägen 14, 230 53, Alnarp, Sweden
| | - Joseph Burman
- Ecology Research Group, Canterbury Christ Church University, North Holmes Road, Canterbury, Kent, CT1 1QU, United Kingdom
| | - Franklin N Nyabuga
- Department of Biological Sciences, University of Embu, P.O. Box 6, 60100, Embu, Kenya
| | - Tobias U T Lindblom
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Box 7043, 750 07, Uppsala, Sweden
| | - Lawrence M Hanks
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Jocelyn G Millar
- Departments of Entomology and Chemistry, University of California, Riverside, CA, 92521, USA
| | - Mattias C Larsson
- Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, Sundsvägen 14, 230 53, Alnarp, Sweden
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Chartier TF, Deschamps J, Dürichen W, Jékely G, Arendt D. Whole-head recording of chemosensory activity in the marine annelid Platynereis dumerilii. Open Biol 2018; 8:180139. [PMID: 30381362 PMCID: PMC6223215 DOI: 10.1098/rsob.180139] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/08/2018] [Indexed: 01/13/2023] Open
Abstract
Chemical detection is key to various behaviours in both marine and terrestrial animals. Marine species, though highly diverse, have been underrepresented so far in studies on chemosensory systems, and our knowledge mostly concerns the detection of airborne cues. A broader comparative approach is therefore desirable. Marine annelid worms with their rich behavioural repertoire represent attractive models for chemosensation. Here, we study the marine worm Platynereis dumerilii to provide the first comprehensive investigation of head chemosensory organ physiology in an annelid. By combining microfluidics and calcium imaging, we record neuronal activity in the entire head of early juveniles upon chemical stimulation. We find that Platynereis uses four types of organs to detect stimuli such as alcohols, esters, amino acids and sugars. Antennae are the main chemosensory organs, compared to the more differentially responding nuchal organs or palps. We report chemically evoked activity in possible downstream brain regions including the mushroom bodies (MBs), which are anatomically and molecularly similar to insect MBs. We conclude that chemosensation is a major sensory modality for marine annelids and propose early Platynereis juveniles as a model to study annelid chemosensory systems.
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Affiliation(s)
- Thomas F Chartier
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Joran Deschamps
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Wiebke Dürichen
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
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Aqrabawi AJ, Kim JC. Hippocampal projections to the anterior olfactory nucleus differentially convey spatiotemporal information during episodic odour memory. Nat Commun 2018; 9:2735. [PMID: 30013078 PMCID: PMC6048034 DOI: 10.1038/s41467-018-05131-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 06/11/2018] [Indexed: 01/13/2023] Open
Abstract
The hippocampus is essential for representing spatiotemporal context and establishing its association with the sensory details of daily life to form episodic memories. The olfactory cortex in particular shares exclusive anatomical connections with the hippocampus as a result of their common evolutionary history. Here we selectively inhibit hippocampal projections to the anterior olfactory nucleus (AON) during behavioural tests of contextually cued odour recall. We find that spatial odour memory and temporal odour memory are independently impaired following inhibition of distinct, topographically organized hippocampal-AON pathways. Our results not only reveal a longstanding unknown function for the AON but offer new mechanistic insights regarding the representation of odours in episodic memory.
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Affiliation(s)
- Afif J Aqrabawi
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada, M5S 3G5
| | - Jun Chul Kim
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada, M5S 3G5.
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada, M5S 3G3.
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10
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Zhao F, Holahan MA, Wang X, Uslaner JM, Houghton AK, Evelhoch JL, Winkelmann CT, Hines CDG. fMRI study of the role of glutamate NMDA receptor in the olfactory processing in monkeys. PLoS One 2018; 13:e0198395. [PMID: 29870538 PMCID: PMC5988321 DOI: 10.1371/journal.pone.0198395] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 05/20/2018] [Indexed: 11/24/2022] Open
Abstract
Studies in rodents show that olfactory processing in the principal neurons of olfactory bulb (OB) and piriform cortex (PC) is controlled by local inhibitory interneurons, and glutamate NMDA receptor plays a role in this inhibitory control. It is not clear if findings from studies in rodents translate to olfactory processing in nonhuman primates (NHPs). In this study, the effect of the glutamate NMDA receptor antagonist MK801 on odorant-induced olfactory responses in the OB and PC of anesthetized NHPs (rhesus monkeys) was investigated by cerebral blood volume (CBV) fMRI. Isoamyl-acetate was used as the odor stimulant. For each NHP, sixty fMRI measurements were made during a 4-h period, with each 4-min measurement consisting of a 1-min baseline period, a 1-min odor stimulation period, and a 2-min recovery period. MK801 (0.3 mg/kg) was intravenously delivered 1 hour after starting fMRI. Before MK801 injection, olfactory fMRI activations were observed only in the OB, not in the PC. After MK801 injection, olfactory fMRI activations in the OB increased, and robust olfactory fMRI activations were observed in the PC. The data indicate that MK801 enhances the olfactory responses in both the OB and PC. The enhancement effects of MK801 are most likely from its blockage of NMDA receptors on local inhibitory interneurons and the attenuation of the inhibition onto principal neurons. This study suggests that the mechanism of local inhibitory control of principal neurons in the OB and PC derived from studies in rodents translates to NHPs.
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Affiliation(s)
- Fuqiang Zhao
- Merck & Co., Inc., West Point, Pennsylvania, United States of America
- * E-mail:
| | - Marie A. Holahan
- Merck & Co., Inc., West Point, Pennsylvania, United States of America
| | - Xiaohai Wang
- Merck & Co., Inc., West Point, Pennsylvania, United States of America
| | - Jason M. Uslaner
- Merck & Co., Inc., West Point, Pennsylvania, United States of America
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Abstract
Agricultural practices require novel products that allow sustainable development and commercial production according to the needs of farmers and consumers. Therefore, in the last decade, eco-friendly alternatives have been studied, so volatile organic compounds (VOCs) emitted by microorganisms have emerged as a cheaper, effective, efficient, and an eco-friendly alternative. VOCs are lipophilic compounds derived from microbial metabolic pathways with low molecular weight (<300 g mol-1), low boiling point, and high vapor pressure that allow them to act as signal molecules over short and long distances. Main case studies provide evidence that VOCs released from diverse microorganisms (i.e. Bacillus, Pseudomonas, Arthrobacter, Fusarium, and Alternaria) can stimulate growth on a specific "target" seedling, such as Arabidopsis and tobacco. Some identified compounds, such as 3-hydroxy-2-butanone (acetoin), 2,3-butanediol, 2-pentylfuran, or dimethylhexadecylmine have shown their ability to elicit growth at root or leaf level. Few studies indicate that VOCs act in the regulation at phytohormone, metabolic pathways and nutrition levels according to genetic, proteomic, and metabolic analyses; but action mechanisms associated with growth-inducing activity are poorly understood. In this work, we reviewed case studies regarding identified compounds and action mechanisms for a better understanding of the information collected so far. Additionally, a brief description about the effects of VOCs for induction of resistance and tolerance in plants are presented, where compounds such as acetoin, dimethyl disulfide, 3-pentanol and 6-pentyl-α-pyrone have been reported. Furthermore, we summarized the knowledge to direct future studies that propose microbial VOCs as a technological innovation in agriculture and horticulture.
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Affiliation(s)
- Paola Fincheira
- Ecological Chemistry Laboratory, Center for Excellence in Biotechnology Research Applied to the Environment (CIBAMA, for its acronyn in Spanish), Faculty of Engineering and Science, Universidad de La Frontera, Av. Francisco Salazar 01145, Temuco, Chile; Universidad de La Frontera, Av. Francisco Salazar 01145, Casilla 54-D, Temuco, Chile
| | - Andrés Quiroz
- Ecological Chemistry Laboratory, Center for Excellence in Biotechnology Research Applied to the Environment (CIBAMA, for its acronyn in Spanish), Faculty of Engineering and Science, Universidad de La Frontera, Av. Francisco Salazar 01145, Temuco, Chile; Department of Chemical Sciences and Natural Resources, Faculty of Engineering and Science, Universidad de La Frontera, Av. Francisco Salazar 01145, Temuco, Chile.
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Hejazi M, Movahedi MF, Askari O, Higbee BS. Novel Chemo-Attractants for Trapping Tomato Leafminer Moth (Lepidoptera: Gelechiidae). J Econ Entomol 2016; 109:2074-2081. [PMID: 27567219 DOI: 10.1093/jee/tow195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 08/11/2016] [Indexed: 06/06/2023]
Abstract
The tomato leafminer moth, Tuta absoluta (Meyrick), is a devastating pest for tomatoes in Iran and throughout the world. This pest reduces tomato yields in farms and greenhouses. It appears some floral odors are significant attractants for tomato leafminer moth. In this study, the effects of three floral compounds, phenylacetaldehyde (PAA), acetic acid (AA), and 3-methyl-1-butanol (MB), were evaluated as trap attractants for tomato leafminer moth. The attractants were tested separately, combined, and blended in binary and tertiary. Lures were tested in delta and water pan traps under field conditions and compared with unbaited traps as controls. Results indicated that water pan traps caught more moths than delta traps. Also treatments with PAA + AA combined and the AA + MB blend were strongly attractive to tomato leafminer moth males compared with other treatments in this study.
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Affiliation(s)
- M Hejazi
- Department of Plant Protection, University of Zanjan, Zanjan, Iran (; )
| | - M F Movahedi
- Department of Plant Protection, University of Zanjan, Zanjan, Iran (; )
| | - O Askari
- Plant Protection Organization, P.O. Box 1454, Tehran 19395, Iran
| | - B S Higbee
- Director, Entomology Research, Wonderful Orchards, 6801 E. Lerdo Hwy, Shafter, CA 93263
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van Loon JJA, Smallegange RC, Bukovinszkiné-Kiss G, Jacobs F, De Rijk M, Mukabana WR, Verhulst NO, Menger DJ, Takken W. Mosquito Attraction: Crucial Role of Carbon Dioxide in Formulation of a Five-Component Blend of Human-Derived Volatiles. J Chem Ecol 2015; 41:567-73. [PMID: 26026743 PMCID: PMC4463982 DOI: 10.1007/s10886-015-0587-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 04/28/2015] [Accepted: 05/01/2015] [Indexed: 01/19/2023]
Abstract
Behavioral responses of the malaria mosquito Anopheles coluzzii (An. gambiae sensu stricto molecular 'M form') to an expanded blend of human-derived volatiles were assessed in a dual-port olfactometer. A previously documented attractive three-component blend consisting of NH3, (S)-lactic acid, and tetradecanoic acid served as the basis for expansion. Adding 4.5% CO2 to the basic blend significantly enhanced its attractiveness. Expansion of the blend with four human-derived C4-volatiles was then assessed, both with and without CO2. Only when CO2 was offered simultaneously, did addition of a specific concentration of 3-methyl-1-butanol or 3-methyl-butanoic acid significantly enhance attraction. The functional group at the terminal C of the 3-methyl-substituted C4 compounds influenced behavioral effectiveness. In the absence of CO2, addition of three concentrations of butan-1-amine caused inhibition when added to the basic blend. In contrast, when CO2 was added, butan-1-amine added to the basic blend strongly enhanced attraction at all five concentrations tested, the lowest being 100,000 times diluted. The reversal of inhibition to attraction by adding CO2 is unique in the class Insecta. We subsequently augmented the three-component basic blend by adding both butan-1-amine and 3-methyl-1-butanol and optimizing their concentrations in the presence of CO2 in order to significantly enhance the attractiveness to An. coluzzii compared to the three- and four-component blends. This novel blend holds potential to enhance malaria vector control based on behavioral disruption.
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Affiliation(s)
- Joop J A van Loon
- Laboratory of Entomology, Wageningen University, P.O. Box 16, 6700 AA, Wageningen, The Netherlands,
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Yang M, Wu H, Lian Y, Li X, Lai F, Zhao G. Influence of organic solvents on catalytic behaviors and cell morphology of whole-cell biocatalysts for synthesis of 5'-arabinocytosine laurate. PLoS One 2014; 9:e104847. [PMID: 25136983 PMCID: PMC4138074 DOI: 10.1371/journal.pone.0104847] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 07/17/2014] [Indexed: 11/21/2022] Open
Abstract
A whole-cell based method was developed for the regioselective synthesis of arabinocytosine laurate. Among the seven kinds of bacteria strains tested in the acylation reaction, Pseudomonas fluorescens gave the highest productivity and a higher 5′-regioselectivity than 99%. Compared with pure organic solvents, the use of organic solvent mixtures greatly promoted the yield of the whole-cell catalyzed reaction, but showed little influence on the 5′-regioselectivity. Of all the tested solvent mixtures, the best reaction result was found in isopropyl ether/pyridine followed by isopentanol/pyridine. However, the whole-cells showed much lower thermostability in isopropyl ether/pyridine than in THF-pyridine. To better understand the toxic effects of the organic solvents on P. fluorescens whole-cells and growing cells were further examined. Significant influences of organic solvents on the biomass of the cells were found, which differed depending on the type of solvents used. SEM analysis visually revealed the changes in the surface morphology of whole-cells and growing cells cultured in media containing various organic solvents, in terms of surface smoothness, bulges and changed cell sizes. Results demonstrated that organic toxicity to cell structure played an important role in whole-cell mediated catalysis.
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Affiliation(s)
- Meiyan Yang
- State Key Lab of Pulp & Paper Making Engineering, South China University of Technology, Guangzhou, China
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China
| | - Hui Wu
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China
| | - Yan Lian
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China
| | - Xiaofeng Li
- State Key Lab of Pulp & Paper Making Engineering, South China University of Technology, Guangzhou, China
- * E-mail: (XL); (GZ)
| | - Furao Lai
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China
| | - Guanglei Zhao
- State Key Lab of Pulp & Paper Making Engineering, South China University of Technology, Guangzhou, China
- * E-mail: (XL); (GZ)
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15
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Ezhov VA, Doronina NV, Trotsenko IA. [Biosynthesis of polyhydroxybutyrate/valerate with different molecular weights during the growth of Methylobacterium extorquens G-10 on a methanol-pentanol mixture]. Prikl Biokhim Mikrobiol 2013; 49:171-174. [PMID: 23795476 DOI: 10.7868/s0555109913020049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The influence of the concentration and time of addition of cosubstrate (pentanol) on the molecular weight (MW) of the polyhydroxybutyrate/valerate (PHBV) copolymer synthesized by Methylobacterium extorquens G-10 during cultivation in a methanol-containing medium has been studied. It was shown that an increase in the pentanol concentration to 20% in a mixture with methanol stimulated the biosynthesis of PHBV with a MW of approximately 1500 kDa and increased the content of valerate up to 50%, especially when pentanol was added to the log phase culture. High pentanol concentrations are toxic for the producer and reduce the total yield of PHBV. An MW increase to 1500 kDa lowers the melting temperature (from 172 to 162 degrees C) and the crystallinity degree (from 63 to 8%) of the biopolymer but increases its elasticity. The revealed variability of PHBV properties extends considerably the potential application areas of synthetic bioplastics.
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Mitchell RF, Hughes DT, Luetje CW, Millar JG, Soriano-Agatón F, Hanks LM, Robertson HM. Sequencing and characterizing odorant receptors of the cerambycid beetle Megacyllene caryae. Insect Biochem Mol Biol 2012; 42:499-505. [PMID: 22504490 PMCID: PMC3361640 DOI: 10.1016/j.ibmb.2012.03.007] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/19/2012] [Accepted: 03/23/2012] [Indexed: 05/05/2023]
Abstract
Odorant receptors (Ors) are a unique family of ligand-gated ion channels and the primary mechanism by which insects detect volatile chemicals. Here, we describe 57 putative Ors sequenced from an antennal transcriptome of the cerambycid beetle Megacyllene caryae (Gahan). The male beetles produce a pheromone blend of nine compovnents, and we functionally characterized Ors tuned to three of these chemicals: receptor McOr3 is sensitive to (S)-2-methyl-1-butanol; McOr20 is sensitive to (2S,3R)-2,3-hexanediol; and McOr5 is sensitive to 2-phenylethanol. McOr3 and McOr20 are also sensitive to structurally-related chemicals that are pheromones of other cerambycid beetles, suggesting that orthologous receptors may be present across many cerambycid species. These Ors are the first to be functionally characterized from any species of beetle and lay the groundwork for understanding the evolution of pheromones within the Cerambycidae.
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Affiliation(s)
- Robert F. Mitchell
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - David T. Hughes
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136
| | - Charles W. Luetje
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136
| | - Jocelyn G. Millar
- Department of Entomology, University of California, Riverside, CA 92521
| | | | - Lawrence M. Hanks
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Hugh M. Robertson
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- To whom correspondence should be addressed. , phone: 217-333-0489, fax: 217-244-3499
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Lin JY, Roman C, St Andre J, Reilly S. Taste, olfactory and trigeminal neophobia in rats with forebrain lesions. Brain Res 2008; 1251:195-203. [PMID: 19059225 DOI: 10.1016/j.brainres.2008.11.040] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2008] [Revised: 11/11/2008] [Accepted: 11/11/2008] [Indexed: 11/19/2022]
Abstract
The present study was designed to examine whether lesions of the insular cortex (IC; Experiment 1), the basolateral amygdala (BLA) or medial amygdala (MeA; Experiment 2) influence the neophobic reactions to orally consumed liquid stimuli. Three different types of stimuli were used: taste (0.5% saccharin), olfactory (0.1% amyl acetate), and trigeminal (0.01 mM capsaicin). Rats with IC, BLA and MeA lesions showed normal responses to the olfactory and trigeminal stimuli. Each type of lesion, however, disrupted the initial occurrence of neophobia to the taste stimulus. The significance of these findings to conditioned taste aversion is discussed.
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Affiliation(s)
- Jian-You Lin
- Department of Psychology, University of Illinois at Chicago, 1007 West Harrison Street, Chicago, IL 60607, USA
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Ozaki K, Ohta A, Iwata C, Horikawa A, Tsuji K, Ito E, Ikai Y, Harada KI. Lysis of cyanobacteria with volatile organic compounds. Chemosphere 2008; 71:1531-1538. [PMID: 18179811 DOI: 10.1016/j.chemosphere.2007.11.052] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 11/20/2007] [Accepted: 11/20/2007] [Indexed: 05/25/2023]
Abstract
One of bacteria collected from Lake Sagami, Japan, Brevibacillus sp., was found to have a lytic activity of cyanobacteria, but did not produce active compounds. Instead, the co-culturing of Microcystis with the Brevibacillus sp. enhanced the production of two volatile compounds, beta-cyclocitral and 3-methyl-1-butanol, and the former had a characteristic lytic activity. It was confirmed that these volatile compounds were derived from the cyanobacteria themselves. beta-Ionone, geosmin and 2-methylisoborneol derived from cyanobacteria and similar volatile compounds, terpenoids, produced by plants also had a lytic activity. The minimum inhibitory concentration values of the cyanobacterial metabolites were estimated to be higher than those of compounds from plants except for a few compounds. Among them, beta-cyclocitral only produced a characteristic color change of culture broth from green to blue. This color change is similar to the phenomenon observed when a sudden decline in growth of cyanobacteria begins in a natural environment.
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Affiliation(s)
- Keiko Ozaki
- Graduate School of Environmental and Human Science, Meijo University, Tempaku, Nagoya 468-8503, Japan.
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Sakagami H, Hashimoto K, Suzuki F, Ishihara M, Kikuchi H, Katayama T, Satoh K. Tumor-specificity and type of cell death induced by vitamin K2 derivatives and prenylalcohols. Anticancer Res 2008; 28:151-158. [PMID: 18383839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Fourteen vitamin K2 (menaquinone (MK)-n, n = 1-14) and ten prenylalcohol derivatives (n = 1-10) with different numbers (n) of isoprenyl groups in the side chains were investigated for their cytotoxicity against nine human tumor cell lines and three human normal oral cells. Among the vitamin K2 derivatives, MK-2 (n = 2) showed the greatest cytotoxicity, followed by MK-1 (n = 1) and MK-3 (n = 3). MK-1, MK-2 and MK-3 showed the highest tumor-specific index (TS= > 2.0, 2.0 and > 1.7, respectively). Among the prenylalcohols, geranylgeraniol (GG) (n = 4) showed the highest cytotoxicity, followed by farnesol (n = 3) and geranylfarnesol (GF) (n = 3). GG showed the highest tumor-specificity (TS = 1.8), followed by farnesol (TS = > 1.4), GF (TS= > < 1.3). However, the tumor-specificity of MK-2 and GG was much lower than that of conventional chemotherapeutic agents. The human leukemic cell lines were the most sensitive, whereas the human glioblastoma cell lines were the most resistant to MK-2 and GG. MK-2 did not induce internucleosomal DNA fragmentation in either the human promyelocytic leukemia HL-60 or the human squamous cell carcinoma HSC-4 cell lines. GG induced marginal internucleosomal DNA fragmentation in the HL-60 cells, but not in the HSC-4 cells. Both MK-2 and GG did not induce the formation of autophagosomes, nor did they clearly change the intracellular concentration of three polyamines. Electron spin resonance (ESR) spectroscopy showed that only MK-1 (n = 1), as well as GGF (n = 7) and GFF (n = 8) which had lower cytotoxicity, produced radicals, suggesting the lack of connection between cytotoxicity and radical production. The present study demonstrates that the presence of 1,4-naphtoquinone structure (including alpha,beta-unsaturated ketones) in vitamin K2 derivatives confers on them the ability to induce non-apoptotic cell death.
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Affiliation(s)
- Hiroshi Sakagami
- Division of Pharmacology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Sakado, Saitama 350-0283, Japan.
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20
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Abstract
BACKGROUND Numerous studies suggest that cAMP signaling pathways play important roles in the development of and predisposition to alcoholism. Our previous study showed that cAMP generation by various isoforms of adenylyl cyclase (AC) exhibits a broad spectrum of responses to ethanol in the human embryonic kidney (HEK) 293 cell system overexpressing individual AC isoforms. These findings suggest that the target of ethanol's action in the cAMP-generating system is AC. However, it is unknown if the action of ethanol is direct or indirect. METHODS The effect of a series of n-alkanols (ethanol to decanol) on dopamine (DA)-stimulated activity of AC isoforms type 6, 7, and 9 (AC6, AC7, and AC9) were examined in transfected HEK293 cells by cAMP accumulation assay. RESULTS n-Alkanols increased DA-stimulated cAMP production in an AC isoform-specific manner, and displayed the alcohol cutoff phenomenon (defined as the carbon chain length beyond which there is no further increase in the potency of an ascending series of n-alkanols). The n-alkanol cutoffs for AC6, AC7, and AC9 are butanol (C4), pentanol (C5), and equal to or greater than decanol (C10), respectively. CONCLUSION The results clearly indicate that, in the HEK293 expression system, the alcohol cutoff effect for n-alkanol potentiation of DA-stimulated AC activity is AC isoform specific. These results strongly suggest that alcohols interact directly with AC molecules.
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Affiliation(s)
- Jinghong Kou
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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21
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Abstract
Sensory receptors often receive strongly dynamic, or time varying, inputs in their natural environments. Characterizing their dynamic properties requires control and measurement of the stimulus over a frequency range that equals or exceeds the receptor response. Techniques for dynamic stimulation of olfactory receptors have lagged behind other major sensory modalities because of difficulties in controlling and measuring the concentration of odorants at the receptor. We present a new method for delivering olfactory stimulation that gives linear, low-noise, wide frequency range control of odorant concentration. A servo-controlled moving bead of silicone elastomer occludes the tip of a Pasteur pipette that releases odorant plus tracer gas into a flow tube. Tracer gas serves as a surrogate indicator of odorant concentration and is measured by a photoionization detector. The system has well-defined time-dependent behavior (frequency response and impulse response functions) and gives predictable control of odorant over a significant volume surrounding the animal. The frequency range of the system is about 0-100 Hz. System characterization was based on random (white noise) stimulation, which allows more rapid and accurate estimation of dynamic behavior than deterministic signals such as sinusoids or step functions. Frequency response functions of Drosophila electroantennograms stimulated by fruit odors were used to demonstrate a typical application of the system.
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Affiliation(s)
- Andrew S French
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H1X5, Canada.
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Grubb BR, Rogers TD, Kulaga HM, Burns KA, Wonsetler RL, Reed RR, Ostrowski LE. Olfactory epithelia exhibit progressive functional and morphological defects in CF mice. Am J Physiol Cell Physiol 2007; 293:C574-83. [PMID: 17428842 DOI: 10.1152/ajpcell.00106.2007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In normal nasal epithelium, the olfactory receptor neurons (ORNs) are continuously replaced through the differentiation of progenitor cells. The olfactory epithelium (OE) of the cystic fibrosis (CF) mouse appears normal at birth, yet by 6 mo of age, a marked dysmorphology of sustentacular cells and a dramatic reduction in olfactory receptor neurons are evident. Electroolfactograms revealed that the odor-evoked response in 30-day-old CF mice was reduced approximately 45%; in older CF mice, a approximately 70% reduction was observed compared with the wild type (WT) response. Consistent with studies of CF airway epithelia, Ussing chamber studies of OE isolated from CF mice showed a lack of forskolin-stimulated Cl(-) secretion and an approximately 12-fold increase in amiloride-sensitive sodium absorption compared with WT mice. We hypothesize that the marked hyperabsorption of Na(+), most likely by olfactory sustentacular cells, leads to desiccation of the surface layer in which the sensory cilia reside, followed by degeneration of the ORNs. The CF mouse thus provides a novel model to examine the mechanisms of disease-associated loss of olfactory function.
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Affiliation(s)
- Barbara R Grubb
- CF/Pulmonary Research and Treatment Center, The University of North Carolina, Chapel Hill, NC 27599-7248, USA.
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23
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Greenberg L, Tröger AG, Francke W, McElfresh JS, Topoff H, Aliabadi A, Millar JG. Queen sex pheromone of the slave-making ant, Polyergus breviceps. J Chem Ecol 2007; 33:935-45. [PMID: 17393281 DOI: 10.1007/s10886-007-9269-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Accepted: 02/21/2007] [Indexed: 10/23/2022]
Abstract
Workers of the slave-making ant, Polyergus breviceps, raid nests of Formica ants and return with Formica pupae that mature into worker ants in the slave-makers' colony. These Formica workers then tend the Polyergus brood, workers, and reproductives. During raids in the mating season, winged virgin Polyergus queens accompany the workers in the raiding columns. During the raid, the virgin queens release a pheromone that attracts males that quickly mate with the queens. We report the identification, synthesis, and bioassay of the sex attractant pheromone of the queens as an approximately 1:6 ratio of (R)-3-ethyl-4-methylpentan-1-ol and methyl 6-methylsalicylate. The ants produce exclusively the (R)-enantiomer of the alcohol, and the (S)-enantiomer has no biological activity, neither inhibiting nor increasing attraction to blends of methyl 6-methylsalicylate with the (R)-enantiomer.
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Affiliation(s)
- Les Greenberg
- Department of Entomology, University of California, Riverside, California 92521, USA.
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Vancetto GT, Ceccato-Antonini SR. MPK1 gene is required for filamentous growth induced by isoamyl alcohol in Saccharomyces cerevisiae strains from the alcoholic fermentation. Appl Microbiol Biotechnol 2007; 75:111-5. [PMID: 17245577 DOI: 10.1007/s00253-006-0795-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Revised: 11/22/2006] [Accepted: 11/25/2006] [Indexed: 10/23/2022]
Abstract
The aim of this study was to evaluate the MPK1 (SLT2) gene deletion upon filamentous growth induced by isoamyl alcohol (IAA) in two haploid industrial strains of Saccharomyces cerevisiae using oligonucleotides especially designed for a laboratory S. cerevisiae strain. The gene deletion was performed by replacing part of the open reading frames from the target gene with the KanMX gene. The recombinant strains were selected by their resistance to G418, and after deletion confirmation by polymerase chain reaction, they were cultivated in a yeast extract peptone dextrose medium + 0.5% IAA to evaluate the filamentous growth in comparison to wild strains. Mpk1 derivatives were obtained for both industrial yeasts showing the feasibility of the oligonucleotides especially designed for a laboratory strain (Sigma1278b) by Martinez-Anaya et al. (In yeast, the pseudohyphal phenotype induced by isoamyl alcohol results from the operation of the morphogenesis checkpoint. J Cell Sci 116:3423-3431, 2003). The filamentation rate in these derivatives was significantly lower for both strains, as induced by IAA. This drastic reduction in the filamentation ability in the deleted strains suggests that the gene MPK1 is required for IAA-induced filamentation response. The growth curves of wild and derivative strains did not differ substantially. It is not known yet whether the switch to filamentous growth affects the fermentative characteristics of the yeast or other physiological traits. A genetically modified strain for nonfilamentous growth would be useful for these studies, and the gene MPK1 could be a target gene. The feasibility of designed oligonucleotides for this deletion in industrial yeast strains is shown.
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Affiliation(s)
- Guilherme Tadeu Vancetto
- Departamento de Tecnologia Agroindustrial e Sócio-Economia Rural, Centro de Ciências Agrárias, Universidade Federal de São Carlos-Campus de Araras, Araras, São Paulo, Brazil
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25
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Otero JM, Soengas RG, Estévez JC, Estévez RJ, Watkin DJ, Evinson EL, Nash RJ, Fleet GWJ. Preliminary Studies on the Transformation of Nitrosugars into Branched Chain Iminosugars: Synthesis of 1,4-Dideoxy-4-C-hydroxymethyl- 1,4-imino-pentanols. Org Lett 2007; 9:623-6. [PMID: 17286369 DOI: 10.1021/ol062887v] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel promising strategy for the transformation of nitrosugars into branched pyrrolidines, based on double Henry reaction with formaldehyde followed by reductive ring closure, allowed the first enantiospecific synthesis of a 4-C-hydroxymethyl branched derivative of the well-known glycosidase inhibitor 1,4-dideoxy-1,4-imino-pentanol. This strategy also afforded a new route to some other interesting derivatives, such as N-hydroxy, N-propyloxy, and imino derivatives, a new kind of compounds with promising biological properties. [reaction: see text].
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Affiliation(s)
- José M Otero
- Departamento de Química OrgAnica, Universidade de Santiago, 15782 Santiago de Compostela, Spain
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Abstract
Human olfaction comprises the opposing actions of excitation and inhibition triggered by odorant molecules. In olfactory receptor neurons, odorant molecules not only trigger a G-protein–coupled signaling cascade but also generate various mechanisms to fine tune the odorant-induced current, including a low-selective odorant inhibition of the olfactory signal. This wide-range olfactory inhibition has been suggested to be at the level of ion channels, but definitive evidence is not available. Here, we report that the cyclic nucleotide-gated (CNG) cation channel, which is a key element that converts odorant stimuli into electrical signals, is inhibited by structurally unrelated odorants, consistent with the expression of wide-range olfactory inhibition. Interestingly, the inhibitory effect was small in the homo-oligomeric CNG channel composed only of the principal channel subunit, CNGA2, but became larger in channels consisting of multiple types of subunits. However, even in the channel containing all native subunits, the potency of the suppression on the cloned CNG channel appeared to be smaller than that previously shown in native olfactory neurons. Nonetheless, our results further showed that odorant suppressions are small in native neurons if the subsequent molecular steps mediated by Ca2+ are removed. Thus, the present work also suggests that CNG channels switch on and off the olfactory signaling pathway, and that the on and off signals may both be amplified by the subsequent olfactory signaling steps.
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Affiliation(s)
- Tsung-Yu Chen
- Center for Neuroscience and Department of Neurology, University of California, Davis, CA 95616, USA.
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27
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Brosnan R, Gong D, Cotten J, Keshavaprasad B, Yost CS, Eger EI, Sonner JM. Chirality in anesthesia II: stereoselective modulation of ion channel function by secondary alcohol enantiomers. Anesth Analg 2006; 103:86-91, table of contents. [PMID: 16790632 DOI: 10.1213/01.ane.0000221437.87338.af] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Chirality has been proposed as a means for distinguishing relevant from irrelevant molecular targets of action, but the sensitivity and specificity of this test is unknown for volatile anesthetics. We applied enantiomers of two chiral anesthetic alcohols (2-butanol and 2-pentanol) that are enantioselective for the minimum alveolar concentration (MAC) preventing movement in 50% of animals and one (2-hexanol) that was not to frog oocytes. Each oocyte expressed one of three anesthetic-sensitive ion channels: a Twik-related-spinal cord K+ (TRESK) channel, a gamma-amino butyric acid type A (GABA(A)) receptor and an N-methyl-d-aspartate (NMDA) receptor. Using voltage-clamp techniques, we found that 2-butanol was not enantioselective for any channel (e.g., 16 mM 2-butanol R(-) and S(-) enantiomers decreased current through an NMDA receptors by 44% +/- 3% [mean +/- se] and 37% +/- 4%, respectively); 2-pentanol was enantioselective for one channel (the GABA(A) receptor, the enantiomers increasing current by 277% +/- 20% and 141% +/- 30%); 2-hexanol was enantioselective for both GABA(A) and NMDA receptors (e.g., decreasing current through the NMDA receptor by 19% +/- 3% and 43% +/- 5%). We calculated the sensitivity and specificity of chirality as a test of anesthetic relevance under two scenarios: 1) all three channels were relevant mediators of MAC and 2) no channel was a mediator of MAC. These sensitivities and specificities were poor because there is no consistent correspondence between receptor and whole animal results. We recommend that enantioselectivity not be used as a test of relevance for inhaled anesthetic targets.
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Affiliation(s)
- Robert Brosnan
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, USA
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28
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Fujita K, Matsuyama A, Kobayashi Y, Iwahashi H. The genome-wide screening of yeast deletion mutants to identify the genes required for tolerance to ethanol and other alcohols. FEMS Yeast Res 2006; 6:744-50. [PMID: 16879425 DOI: 10.1111/j.1567-1364.2006.00040.x] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
A set of homozygous diploid deletion mutants of the yeast Saccharomyces cerevisiae was screened for the genes required for tolerance to aliphatic alcohols. The screen identified 137, 122 and 48 deletion mutants sensitive to ethanol, 1-propanol and 1-pentanol, respectively. A number of the genes required for ethanol tolerance were those also required for tolerance to other alcohols. Numerous mutants with defective genes encoding for vacuolar H+ -ATPase (V-ATPase) were cosensitive to these alcohols. A global screening approach of yeast deletion library mutants was useful in elucidating the mechanisms of alcohol tolerance based on different lipophilicities.
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Abstract
In experimental practice, odors are commonly applied to only one nostril for recordings of olfactory event-related potentials (OERPs), but the lateralization aspect of the OERP response is unclear regarding both stimulated nostril and cortical topography. The purpose of the present study was to investigate whether stimulated-nostril side affects OERP amplitudes and latencies and whether these potentials indicate lateralization of brain response in healthy, right-handed, young adults. OERPs were recorded from nine electrode sites in response to monorhinal stimulation with amyl acetate in 28 participants. The results showed a general increase in amplitude from frontal to parietal electrode sites (in particular for N1/P3) and generally larger amplitudes on the left hemisphere and midline than on the right hemisphere. There was no main effect of stimulated-nostril side on amplitude. Interactions indicated that N1/P2 amplitude was larger for left- than right-nostril stimulation and larger on the left hemisphere and midline than on the right hemisphere in left-nostril stimulation. No main effect or interactions of stimulated-nostril side over latencies were found and no effects on latencies of sagittal or coronal sites. These findings suggest a general parietal, left-hemisphere predominance in response amplitude to odorous stimulation and imply that either the left or the right nostril may be sufficient for accurate assessment of OERP latency in right-handed, young adults.
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30
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Bhandari P, Gargano JW, Goddeeris MM, Grotewiel MS. Behavioral Responses to Odorants in Drosophila Require Nervous System Expression of the Integrin Gene Myospheroid. Chem Senses 2006; 31:627-39. [PMID: 16763085 DOI: 10.1093/chemse/bjl002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Integrins are cell adhesion molecules that mediate numerous developmental processes in addition to a variety of acute physiological events. Two reports implicate a Drosophila beta integrin, betaPS, in olfactory behavior. To further investigate the role of integrins in Drosophila olfaction, we used Gal4-driven expression of RNA interference (RNAi) transgenes to knock down expression of myospheroid (mys), the gene that encodes betaPS. Expression of mys-RNAi transgenes in the wing reduced betaPS immunostaining and produced morphological defects associated with loss-of-function mutations in mys, demonstrating that this strategy knocked down mys function. Expression of mys-RNAi transgenes in the antennae, antennal lobes, and mushroom bodies via two Gal4 lines, H24 and MT14, disrupted olfactory behavior but did not alter locomotor abilities or central nervous system structure. Olfactory behavior was normal in flies that expressed mys-RNAi transgenes via other Gal4 lines that specifically targeted the antennae, the projection neurons, the mushroom bodies, bitter and sweet gustatory neurons, or Pox neuro neurons. Our studies confirm that mys is important for the development or function of the Drosophila olfactory system. Additionally, our studies demonstrate that mys is required for normal behavioral responses to both aversive and attractive odorants. Our results are consistent with a model in which betaPS mediates events within the antennal lobes that influence odorant sensitivity.
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Affiliation(s)
- Poonam Bhandari
- Department of Human Genetics, Virginia Commonwealth University, Richmond, 23298, USA
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31
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Gouinguené SP, Städler E. Oviposition in Delia platura (Diptera, Anthomyiidae): The Role of Volatile and Contact Cues of Bean. J Chem Ecol 2006; 32:1399-413. [PMID: 16718565 DOI: 10.1007/s10886-006-9058-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Revised: 02/16/2006] [Accepted: 02/21/2006] [Indexed: 10/24/2022]
Abstract
The choice of a suitable oviposition site by female insects is essential for survival of their progeny. Both olfactory and contact cues of the oviposition site may mediate this choice. The polyphagous Delia platura (Diptera: Anthomyiidae), a severe agricultural pest of numerous crops, lays eggs in the soil close to germinating seeds. Maggots feed upon the cotyledons. Only little is known about the cues guiding oviposition behavior. In this study, the effects of both olfactory and contact cues of beans (Phaseolus vulgaris) on oviposition of D. platura females were tested. Egg deposition on germinated beans was preferred to egg deposition on ungerminated beans or on beans in different postgerminating developmental stages. Olfactory cues of germinating beans alone stimulated female flies to lay eggs. Additional contact cues of germinating beans seemed to enhance the response, but the difference was not significant. Surface extracts of germinating beans sprayed on surrogate beans showed that both polar and nonpolar substances stimulated oviposition of D. platura flies. Gas chromatography-electroantennographic detection recordings of head space samples of germinating beans showed positive response of females to different compounds. We conclude that olfaction plays a major role when D. platura females are searching for oviposition sites. Volatile compounds released from germinating beans such as 4-hydroxy-4-methyl-2-pentanone, 1-hepten-3-one, 1-octen-3-ol, and 3-octanone should be considered as key compounds that mediate oviposition behavior. The use of different sensory modalities by closely related species of Delia is discussed.
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Jacob TJC, Wang L. A new method for measuring reaction times for odour detection at iso-intensity: Comparison between an unpleasant and pleasant odour. Physiol Behav 2006; 87:500-5. [PMID: 16469339 DOI: 10.1016/j.physbeh.2005.11.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 11/10/2005] [Accepted: 11/21/2005] [Indexed: 11/26/2022]
Abstract
A psychophysical detection test was developed to measure the reaction time of human subjects to a pleasant and an unpleasant odour. The response latencies to stimulation with a malodour (valeric acid) and pleasant odorant (amyl acetate) were compared over a range of different stimulus strengths. By expressing reaction time as a function of detection rate, the responses to the two odours can be compared at iso-intensity across the concentration range. This is the first study that allows odorants to be compared at the same intensity over a range of concentrations. The malodour valeric acid was detected more rapidly than amyl acetate; at the 50% detection level the reaction time for the detection of amyl acetate was 1.74 s compared 1.36 s for valeric acid (380 ms or 22% faster). Women were significantly faster than men at detecting both the unpleasant (by 18%) and pleasant (by 26%) odour at the 50% detection level and this disparity increased with decreasing stimulus strength. In conclusion, we demonstrate the ability of a new method for the measurement of reaction times to odour detection to discriminate between two different odours - a malodour and a non-malodour.
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Affiliation(s)
- Tim J C Jacob
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3US, UK.
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33
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Peterschmitt Y, Hoeltzel A, Louilot A. Striatal dopaminergic responses observed in latent inhibition are dependent on the hippocampal ventral subicular region. Eur J Neurosci 2005; 22:2059-68. [PMID: 16262643 DOI: 10.1111/j.1460-9568.2005.04366.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We showed recently that behavioural and striatal dopaminergic (DA) responses obtained in latent inhibition are crucially dependent on the parahippocampal region, the entorhinal cortex. In the present study, we investigated the influence exerted by the hippocampal ventral subicular region (SUB) on the DA responses in the anterior part of the dorsal striatum using in vivo voltammetry in freely moving rats and the same latent inhibition paradigm. To that end, the left SUB was temporarily blocked with tetrodotoxin (TTX) during pre-exposure to a new olfactory stimulus (banana odour). During the second session the animals were aversively conditioned to banana odour. With respect to the results obtained during the test session (third presentation of banana odour), similar changes in behaviour and DA levels were obtained in control and conditioned rats microinjected with the solvent, phosphate-buffered saline (PBS), in the SUB, consistently with a latent inhibition phenomenon. In contrast, after reversible inactivation of the SUB during the pre-exposure session, TTX-pre-exposed conditioned animals displayed aversive behaviour in the test session, and anterior striatal DA variations in these animals differed significantly from those obtained in pre-exposed rats injected locally with PBS. Striatal DA variations obtained in conditioned animals microinjected with TTX were also significantly different from those observed in conditioned non-pre-exposed animals. The present data suggest that, in parallel to the entorhinal cortex, the SUB regulates the latent inhibition-related behavioural and DA responses in the anterior part of the dorsal striatum. These data may provide new insight into the pathophysiology of schizophrenic psychoses.
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Affiliation(s)
- Y Peterschmitt
- INSERM U 666 and Institute of Physiology, Louis Pasteur University, Faculty of Medicine, 11 rue Humann, 67085 Strasbourg CEDEX, France
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Kern K, Nunn CD, Pichová A, Dickinson JR. Isoamyl alcohol-induced morphological change in Saccharomyces cerevisiae involves increases in mitochondria and cell wall chitin content. FEMS Yeast Res 2005; 5:43-9. [PMID: 15381121 DOI: 10.1016/j.femsyr.2004.06.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2004] [Revised: 05/03/2004] [Accepted: 06/07/2004] [Indexed: 11/29/2022] Open
Abstract
Isoamyl alcohol reduced growth and induced filament formation in Saccharomyces cerevisiae. Isoamyl alcohol-induced filamentation was accompanied by an almost threefold greater increase in the specific activity of succinate dehydrogenase than in untreated cells, which suggested that isoamyl alcohol treatment caused the cells to produce more mitochondria than in normal yeast form proliferation. This was supported by measuring the dry weight of purified, isolated mitochondria. Filaments have an increased chitin content which is distributed over the majority of their surface, and is not confined to bud scars and the chitin ring between mother and daughter cells as in yeast-form cells.
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Affiliation(s)
- Kerstin Kern
- Cardiff School of Biosciences, Cardiff University, P.O. Box 915, Cardiff CF10 3TL, UK
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35
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Korneev SA, Straub V, Kemenes I, Korneeva EI, Ott SR, Benjamin PR, O'Shea M. Timed and targeted differential regulation of nitric oxide synthase (NOS) and anti-NOS genes by reward conditioning leading to long-term memory formation. J Neurosci 2005; 25:1188-92. [PMID: 15689555 PMCID: PMC6725956 DOI: 10.1523/jneurosci.4671-04.2005] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In a number of neuronal models of learning, signaling by the neurotransmitter nitric oxide (NO), synthesized by the enzyme neuronal NO synthase (nNOS), is essential for the formation of long-term memory (LTM). Using the molluscan model system Lymnaea, we investigate here whether LTM formation is associated with specific changes in the activity of members of the NOS gene family: Lym-nNOS1, Lym-nNOS2, and the antisense RNA-producing pseudogene (anti-NOS). We show that expression of the Lym-nNOS1 gene is transiently upregulated in cerebral ganglia after conditioning. The activation of the gene is precisely timed and occurs at the end of a critical period during which NO is required for memory consolidation. Moreover, we demonstrate that this induction of the Lym-nNOS1 gene is targeted to an identified modulatory neuron called the cerebral giant cell (CGC). This neuron gates the conditioned feeding response and is an essential part of the neural network involved in LTM formation. We also show that the expression of the anti-NOS gene, which functions as a negative regulator of nNOS expression, is downregulated in the CGC by training at 4 h after conditioning, during the critical period of NO requirement. This appears to be the first report of the timed and targeted differential regulation of the activity of a group of related genes involved in the production of a neurotransmitter that is necessary for learning, measured in an identified neuron of known function. We also provide the first example of the behavioral regulation of a pseudogene.
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Affiliation(s)
- Sergei A Korneev
- Sussex Centre for Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom.
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36
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Deshpande A, Nimsadkar S, Mande SC. Effect of alcohols on protein hydration: crystallographic analysis of hen egg-white lysozyme in the presence of alcohols. Acta Crystallogr D Biol Crystallogr 2005; 61:1005-8. [PMID: 15983424 DOI: 10.1107/s0907444905009364] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Accepted: 03/23/2005] [Indexed: 11/10/2022]
Abstract
Organic solvents are known to bring about dehydration of proteins, the molecular basis of which has remained uncharacterized. The dehydration effect in many cases leads to eventual unfolding of proteins through the macroscopic solvent effect. In some cases, the organic solvent molecules also bind to protein surfaces, thereby forcing local unfolding. The X-ray structure of hen egg-white lysozyme co-crystallized in the presence of alcohols with varying hydrophobicities has been studied. It was noticed that although the alcohols have very little effect on the conformation of the overall protein structure, they profoundly affect protein hydration and disorder of the bound waters. Systematic analysis of the water structure around the lysozyme molecule suggests that an increasing order of hydrophobicity of alcohols is directly proportional to the higher number of weakly bound waters in the protein. As anticipated, the water molecules in the native structure with high temperature factors (>/=40 A(2)) attain higher disorder in the presence of alcohols. It is believed that the disorder induced in the water molecules is a direct consequence of alcohol binding.
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Affiliation(s)
- Ashlesha Deshpande
- Centre for DNA Fingerprinting and Diagnostics, ECIL Road, Nacharam, Hyderabad 500076, India
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37
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Bordeleau LJ, Gailis L, Fournier D, Morissette M, Di Paolo T, Daleau P. Cut-off phenomenon in the protective effect of alcohols against lysophosphatidylcholine-induced calcium overload. Pflugers Arch 2005; 450:292-7. [PMID: 15909177 DOI: 10.1007/s00424-005-1425-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Accepted: 03/24/2005] [Indexed: 01/13/2023]
Abstract
We studied the effect of chain length on the protective effect of alcohols against lysophosphatidylcholine (LPC)-induced Ca2+ overload in neonatal rat cardiomyocytes. We previously found that ethanol retards Ca2+ elevation. Cells were loaded with the Ca2+-sensitive fluorophore fura-2, and changes in fluorescence were followed. The addition of 10 microM LPC increased Ca2+, which reached a plateau after an 8-10 min delay. The presence of 88 mM n-propanol, n-butanol, tert-butanol, or 2,2-dimethylpropanol significantly increased the delay by 94-213%. However, n-pentanol at 2 mM or 88 mM had no protective effect. Among n-alcohols, the increase in lag time was inversely proportional to the length of the carbon chain. Chain length, rather than molecular weight determines the effect, because 2,2-dimethylpropanol had a protective effect. The influence of alcohols on LPC micelle formation was estimated from the increase in octadecyl rhodamine B fluorescence; the increase by n-alcohols was directly proportional to chain length, indicating that micelle formation was not involved in the extension of lag time. The absence of the protective effect when the alcohol aliphatic chain exceeds four carbons suggests that the effect of ethanol may be mediated via a small lipophilic pocket on a protein, or to lateral pressure perturbation in the membrane.
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Affiliation(s)
- Louis-Jean Bordeleau
- Quebec Heart Institute, Laval Hospital Research Center, 2725 chemin Ste-Foy, Ste-Foy, QC, Canada, G1V 4G5
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Jung Y, Wirkus E, Amendola D, Gomez G. Characteristics of odorant elicited calcium fluxes in acutely-isolated chick olfactory neurons. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2005; 191:511-20. [PMID: 15838651 DOI: 10.1007/s00359-005-0617-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2004] [Revised: 01/24/2005] [Accepted: 02/05/2005] [Indexed: 10/25/2022]
Abstract
To understand avian olfaction, it is important to characterize the peripheral olfactory system of a representative bird species. This study determined the functional properties of olfactory receptor neurons of the chicken olfactory epithelium. Individual neurons were acutely isolated from embryonic day-18 to newborn chicks by dissection and enzymatic dissociation. We tested single olfactory neurons with behaviorally relevant odorant mixtures and measured their responses using ratiometric calcium imaging; techniques used in this study were identical to those used in other studies of olfaction in other vertebrate species. Chick olfactory neurons displayed properties similar to those found in other vertebrates: they responded to odorant stimuli with either decreases or increases in intracellular calcium, calcium increases were mediated by a calcium influx, and responses were reversibly inhibited by 100 microM L: -cis-diltiazem, 1 mM Neomycin, and 20 microM U73122, which are biochemical inhibitors of second messenger signaling. In addition, some cells showed a complex pattern of responses, with different odorant mixtures eliciting increases or decreases in calcium in the same cell. It appears that there are common features of odorant signaling shared by a variety of vertebrate species, as well as features that may be peculiar to chickens.
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Affiliation(s)
- Yewah Jung
- Biology Department, University of Scranton, Scranton, PA 18510, USA
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39
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Abstract
By optical imaging of intrinsic signals, we demonstrated a possible code for odor concentration in the anterior piriform cortex of the guinea-pig. Odor-induced cortical activation, which primarily originated in layer II, appeared in a narrow band beneath the rhinal sulcus over the lateral olfactory tract, corresponding to the dorsal part of the anterior piriform cortex. Lower concentrations activated the rostral region of the band, whereas higher ones generated caudally spreading activation, and the site at which neural activation reached its maximum extent depended upon odor concentration. Different odors with low concentrations generated distinct but somewhat overlapping patterns in the rostral region of the band; the limited extent of cortical activity may be one focal domain for each odor. It was hard to judge, however, that odor-specific domains appeared in the anterior piriform cortex, because the strong stimuli induced largely overlapping patterns. Furthermore, the total area activated increased in proportion to concentrations raised to a power of 0.5-0.9. Importantly, these imaging results were confirmed with unit recordings which indicated a rostro-caudal gradient in odor-sensitivity among cortical neurons. Our results suggest that the dorsal part of the anterior piriform cortex may be associated with odor concentration. Therefore, in addition to recruitment of more olfactory sensory cells and glomeruli in response to stronger stimuli, a rostro-caudal gradient in axonal projections from mitral/tufted cells and/or in association fibers may play an important role in odor-concentration coding in the anterior piriform cortex.
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Affiliation(s)
- T Sugai
- Department of Physiology, Kanazawa Medical University, Uchinada, Ishikawa 920-0293, Japan
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40
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Jones SV, Heldt SA, Davis M, Ressler KJ. Olfactory-mediated fear conditioning in mice: simultaneous measurements of fear-potentiated startle and freezing. Behav Neurosci 2005; 119:329-35. [PMID: 15727538 PMCID: PMC2881597 DOI: 10.1037/0735-7044.119.1.329] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study demonstrates that mice display olfactory-cued fear as measured with both freezing and fear-potentiated startle. Following a preconditioning test to measure any unconditioned responses to odor, mice received 5 pairings of a 10-s odor with a 0.25-s, 0.4-mA footshock. The next day, startle and freezing were measured in the presence and absence of the odor. Both fear measures increased after training with amyl acetate (Experiment 1) and acetophenone (Experiment 2). The enhancement of startle did not occur when the same number of odors and shocks were presented in an unpaired fashion (Experiment 3). Furthermore, mice were able to discriminate between an odor paired with shock and a nonreinforced odor (Experiment 4).
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Affiliation(s)
- Seth V Jones
- Department of Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA
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41
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Wolf KK, Wood SG, Bement JL, Sinclair PR, Wrighton SA, Jeffery E, Gonzalez FJ, Sinclair JF. Role of mouse CYP2E1 in the O-hydroxylation of p-nitrophenol: comparison of activities in hepatic microsomes from Cyp2e1(-/-) and wild-type mice. Drug Metab Dispos 2005; 32:681-4. [PMID: 15205381 DOI: 10.1124/dmd.32.7.681] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Enzymatic activities are routinely used to identify the contribution of individual forms of cytochrome P450 in a particular biotransformation. p-Nitrophenol O-hydroxylation (PNPH) has been widely used as a measure of CYP2E1 catalytic activity. However, rat and human forms of CYP3A have also been shown to catalyze this activity. In mice, the contributions of CYP3A and CYP2E1 to PNPH activity are not known. Here we used hepatic microsomes from Cyp2e1(-/-) and wild-type mice to investigate the contributions of constitutively expressed and alcohol-induced murine CYP2E1 and CYP3A to PNPH activity. In liver microsomes from untreated mice, PNPH activity was much greater in wild-type mice compared with Cyp2e1(-/-) mice, suggesting a major role for CYP2E1 in catalyzing PNPH activity. Hepatic PNPH activities were not significantly different in microsomes from male and female mice, although the microsomes from females have dramatically higher levels of CYP3A. Treatment with a combination of ethanol and isopentanol resulted in induction of CYP3A proteins in wild-type and Cyp2e1(-/-) mice, as well as CYP2E1 protein in wild-type mice. The alcohol treatment increased PNPH activities in hepatic microsomes from wild-type mice but not from Cyp2e1(-/-) mice. Our findings suggest that in untreated and alcohol-treated mice, PNPH activity may be used as a specific probe for CYP2E1 and that constitutively expressed and alcohol-induced forms of mouse CYP3A have little to no role in catalyzing PNPH activity.
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Affiliation(s)
- Kristina K Wolf
- Veterans Administration Medical Center, White River Junction, VT 05009, USA
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42
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Centrone CA, Lowary TL. Sulfone and phosphinic acid analogs of decaprenolphosphoarabinose as potential anti-tuberculosis agents. Bioorg Med Chem 2004; 12:5495-503. [PMID: 15465326 DOI: 10.1016/j.bmc.2004.08.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Revised: 07/30/2004] [Accepted: 08/12/2004] [Indexed: 10/26/2022]
Abstract
Mycobacteria biosynthesize a cell wall structure that is rich in polysaccharides containing arabinofuranose residues. The source of these arabinofuranose residues is decaprenolphosphoarabinose (1), the donor substrate for mycobacterial arabinosyltransferases. We have previously demonstrated that an analog of 1, C-phosphonate 7, prevented the growth of mycobacteria and this compound is currently undergoing testing for efficacy in tuberculosis-infected mice. We describe here the synthesis and testing of additional analogs of 1 that contain either a sulfone (8-14) or phosphinic acid (15-19) moiety in place of the phosphodiester functionality. Screening of these compounds in vitro against Mycobacterium tuberculosis strain H(37)Rv revealed that while some of these compounds possessed low to modest activity, none was as potent as 7.
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Affiliation(s)
- Charla A Centrone
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
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Wang L, Hari C, Chen L, Jacob T. A new non-invasive method for recording the electro-olfactogram using external electrodes. Clin Neurophysiol 2004; 115:1631-40. [PMID: 15203064 DOI: 10.1016/j.clinph.2004.02.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVE The aim of this investigation was to explore the possibility of recording the electro-olfactogram (EOG) using external electrodes placed on the root of the nose on either side of the bridge and at the medial termination of the eyebrows. The EOG is considered to be the summated generator potential of olfactory receptor cells and therefore represents peripheral olfactory events. Recording of human EOG is technically difficult due to poor access to the olfactory mucosa and the nasal irritation is tolerated by few subjects. METHODS The evoked potentials at these sites in response to two odourants, n-amyl acetate and benzaldehyde, were recorded simultaneously with the EOG, recorded conventionally with an intranasal electrode, and the olfactory event-related potential (OERP) recorded using scalp electrodes. RESULTS The extranasal potential recorded at the root of the nose, 0.5-1 cm below the nasion, 1 cm from the ridge and ipsilateral with the stimulus, had the highest degree of correlation with the intranasal EOG. We refer to this site as N1 (left side) and N2 (right side). Further analysis demonstrated that the latency, the time constant of the rising phase and the amplitude of the evoked potential recorded at N1 also had a higher correlation coefficient with the EOG than did those potentials recorded at other sites. Statistical analysis indicated that the latency and time constant of the response recorded externally at N1 were the same as those of the EOG recorded intranasally. CONCLUSIONS We conclude that an olfactory evoked potential, with many of the characteristics of the EOG recorded from the olfactory mucosa, can be recorded externally at a site close to the bridge of the nose. SIGNIFICANCE This non-invasive method of recording the EOG will have benefits for the objective assessment of olfactory function.
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Affiliation(s)
- Liwei Wang
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3US, UK
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Fujita K, Matsuyama A, Kobayashi Y, Iwahashi H. Comprehensive gene expression analysis of the response to straight-chain alcohols in Saccharomyces cerevisiae using cDNA microarray. J Appl Microbiol 2004; 97:57-67. [PMID: 15186442 DOI: 10.1111/j.1365-2672.2004.02290.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIMS The purpose of this study was to examine the gene expression profiles of yeast Saccharomyces cerevisiae subjected to straight-chain alcohols. METHODS AND RESULTS Lipophilic alcohols with high log Pow values were more toxic to yeast than those with low log Pow values. Morphological changes after exposure to ethanol, 1-pentanol, 1-octanol were observed, whereas n-pentane as a model hydrocarbon affected the surface of the outer membrane, with little change in organelles. Using cDNA microarrays, quite a few up-regulated gene categories were classified into the category 'cell rescue, defence and virulence' by ethanol, and the category 'energy' and 'metabolism' by 1-pentanol. Meanwhile, the characteristic genes up-regulated by n-pentane were not observed, and the expression profile was distantly related to ethanol, 1-pentanol and 1-octanol. CONCLUSIONS This study suggests that gene expression profiles at the whole genome level were intimately associated with the cell growth inhibition and morphological changes by straight-chain alcohols with differing log Pow values. SIGNIFICANCE AND IMPACT OF THE STUDY The study of comprehensive gene expression profiles by cDNA microarrays elucidates the straight-chain alcohol adaptation mechanisms.
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Affiliation(s)
- K Fujita
- Japan Bioindustry Association (JBA), Daicel Chemical Industries, Ltd, Branch, Tsukuba, Japan.
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Abstract
A learning event can be dissociated into 3 components: acquisition, storage, and recall. When the laboratory wild-type strain of Caenorhabditis elegans (N2 strain) is exposed to benzaldehyde in the absence of food, the worms display a reduction of their attractive response to this volatile odorant. This results from the association between benzaldehyde and a nutrient-deficient environment. Another wild-type isolate, the CB4856 strain, fails to display this decreased response to benzaldehyde after exposure to benzaldehyde in the absence of food. However, like the N2 strain, when tested to isoamyl alcohol after benzaldehyde conditioning, the CB4856 strain displays a decreased isoamyl alcohol response. Therefore, the CB4856 strain does not have an acquisition deficit, but it suffers from a recall deficit specific to benzaldehyde.
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Walker JC, Hall SB, Walker DB, Kendal-Reed MS, Hood AF, Niu XF. Human Odor Detectability: New Methodology Used to Determine Threshold and Variation. Chem Senses 2003; 28:817-26. [PMID: 14654450 DOI: 10.1093/chemse/bjg075] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Current ambiguity concerning the related issues of optimal means for measurement of odor sensitivity and the functional properties of the olfactory system hinders progress in basic and applied research on the human sense of smell. To address these needs, we selected n-amyl acetate (nAA) as a test odorant and developed a methodology in which participants (Ps) receive multiple presentations each session of several concentrations. Yes-no responses as to whether odor was detected are analyzed using binomial statistics, with the probability that a given proportion of yes responses (or greater) would occur by chance alone being treated as the inverse of detectability. Over the course of multiple sessions, this information is also used to maximize the collection of data in the peri-threshold region. Surprisingly, data collected over as many as 14 sessions were fit well by a single logistic regression model relating probability and concentration. Threshold concentrations, defined as those corresponding to a probability of 0.05, varied from 7.11 to 167.53 p.p.b. (v/v) for 11 Ps. Our approach and findings, if shown to be representative of other combinations of Ps and odorants, could accelerate the pace of research in human olfaction by providing a comprehensive operational definition of the limit of the olfactory system to detect odorant molecules.
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Affiliation(s)
- James C Walker
- Sensory Research Institute, Florida State University, 1800 E Paul Dirac Drive, Tallahassee, FL 32306-2741 USA.
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Martinez-Anaya C, Dickinson JR, Sudbery PE. In yeast, the pseudohyphal phenotype induced by isoamyl alcohol results from the operation of the morphogenesis checkpoint. J Cell Sci 2003; 116:3423-31. [PMID: 12840070 DOI: 10.1242/jcs.00634] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Isoamyl alcohol (IAA) induces a phenotype that resembles pseudohyphae in the budding yeast Saccharomyces cerevisiae. We show here that IAA causes the rapid formation of linear chains of anucleate buds, each of which is accompanied by the formation of a septin ring at its neck. This process requires the activity of Swe1 and Slt2 (Mpk1). Cdc28 is phosphorylated on tyrosine 19 in a Swe1-dependent manner, while Slt2 becomes activated by dual tyrosine/threonine phosphorylation. Tyrosine 19 phosphorylation of Cdc28 is not dependent on Slt2. However, the defective response in the slt2Delta mutant is rescued by an mih1Delta mutation. The IAA response still occurs in a cell containing a dominant non-phosphorylatable form of Cdc28, but no longer occurs in an mih1Delta slt2Delta mutant containing this form of Cdc28. These observations show that IAA induces the Swe1-dependent morphogenesis checkpoint and so the resulting pseudohyphal phenotype arises in an entirely different way from the formation of pseudohyphae induced by nitrogen-limited growth.
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Affiliation(s)
- Claudia Martinez-Anaya
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
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Abstract
Up to 74 people die each year in Japan after being stung by Hymenopteran insects, with hornets (Vespa spp.) being among the worst offenders. Here we identify a volatile, multi-component alarm pheromone in the venom of the world's largest hornet, V. mandarinia, and use field bioassays to show that 2-pentanol is its principal active component, and that 3-methyl-1-butanol and 1-methylbutyl 3-methylbutanoate act synergistically with it. The compound 1-methylbutyl 3-methylbutanoate, which may also be a foraging-site-marking pheromone, elicits a strong defensive reaction in the sympatric prey hornet V. simillima xanthoptera. As these chemicals are sometimes used in food flavourings and as fragrances in cosmetics, it is possible that they might provoke a seemingly unwarranted hornet attack on humans.
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Affiliation(s)
- Masato Ono
- Centre of Excellence Integrative Human Science Program, Research Institute and Graduate School of Agriculture, Machida, Tokyo 194-8610, Japan.
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Fraud S, Rees EL, Mahenthiralingam E, Russell AD, Maillard JY. Aromatic alcohols and their effect on Gram-negative bacteria, cocci and mycobacteria. J Antimicrob Chemother 2003; 51:1435-6. [PMID: 12716779 DOI: 10.1093/jac/dkg246] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Abstract
We studied the outward currents elicited by an odorous compound, isoamyl acetate, in isolated olfactory receptor neurons of the grass frog under whole-cell perforated-patch voltage-clamp recording. Odorant-induced outward currents were relatively rare, occurring in about 16% of the responding cells. Responses had smaller amplitudes and shorter time courses when compared to the more commonly found odorant-induced inward currents. There was a high correlation between odorant-induced outward current and responses evoked by either 8-(4-chlorophenylthio) adenosine 3':5'-cyclic monophosphate, a membrane-permeant cyclic adenosine monophosphate analog, or 3-isobutyl-1-methylxanthine, a phosphodiesterase inhibitor. The outward current responses to all three substances increased in amplitude when the membrane potential was more negative than -60 mV and decreased in amplitude when the membrane potential was more positive. Responses were still present when the potential was held at -100 mV, indicating that the responses are not the result of a potassium conductance. Removal of external calcium from the perfusion medium abolished the outward currents. Our results indicate that the odorant-induced outward current is a calcium-dependent event that may be mediated by cyclic adenosine monophosphate.
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Affiliation(s)
- Raymund Y K Pun
- Department of Molecular and Cellular Physiology, University of Cincinnati, OH 45267-0576, USA.
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