Progress in Research on Insect Olfactory Perception of Habitat Odor Molecules

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

No evidence of predator odor avoidance in a North American bird community

Recent advances in our understanding of avian chemical communication have highlighted the importance of olfaction in many aspects of avian life.Prior studies investigating predator avoidance behaviors in response to predator odor cues have produced mixed results across species and contexts.Here we assess if a community of birds in eastern Pennsylvania displays avoidance behaviors towards predator odor cues in a natural foraging setting.We use clay caterpillars to measure foraging activity by birds in the presence of predator(bobcat)urine,non-predator(rabbit)urine,and water controls in two different environmental contexts(field vs.forest).Although we detected a weak trend for birds to forage less at predator urine-treated sites,we found no significant difference in avian foraging between the site types.We did find that foraging rates between environmental contexts changed significantly over the course of the experiment,with forest sites showing decreasing foraging rates and field sites showing increasing foraging rates.Our results reinforce the published literature that avoidance of predator odors by birds may not be ubiquitous across contexts and species.

Volatile Solid and Bury Period Influence on Odorous Material Production in Simulating Landfill Treatment

Odor pollution in landfill area has attracted more social attention in China. It is very important to control the generation of odor pollutants in situ. Analyzing odorous materials production form buried waste, simulated columns of different volatile solid (VS) content and different buried period waste were designed. Gas compounds produced from the columns were collected and analyzed by comprehensive two-dimensional gas chromatography (GC × GC) method. It has remarkable relationship between VS content and concentrations of odorous material. When VS content more than 40%, the total amount of odorous compounds increases remarkably. It can be inferred that reduced VS content of original waste may effective decreasing odorous materials production in landfill area. The old rubbish produced more odorous compounds than that of fresh one in simulated columns.

20 ppm Anhydrous Ammonia Odor Agent Proposed for Hydrogen Fuel for Safe Detection of Leaks

Preferably 20 ppm anhydrous ammonia (NH3) is proposed to be added to hydrogen fuel (H) made from renewable energy sources (green hydrogen), so that H leaks may be easily detectable by smell, but not dangerously toxic. Including this odor agent, would allow H to be distributed safely in pipes, as required by law, and it would allow H to be safely stored, transported, and exported for sale, and widely commercialized. Further research is suggested to identify optimum pressure, temperature, and automated technique for injecting NH3 into H, and to chart the minimum concentration needed, as a function of temperature and humidity. An application to make hypersonic H burning aircraft safer for ground maintenance crews is proposed. An ability to make, store and distribute H, made from local sources of renewable energy, would reduce a need for fossil fuels, especially in poor, remote communities, where it could improve their economy by creating an export product for sale, while reducing pollution.

Characterization of the key aroma compounds in four varieties of pomegranate juice by gas chromatography-mass spectrometry(GC-MS),gas chromatography-olfactometry(GC-O),odor activity value(OAV),aroma recombination,and omission tests

P omegranate(Punica granatum L.)has attracted considerable attention in world markets due to its valuable nutrients and highly appreciated sensory properties.The aroma profiles of 4 varieties of pomegranate juice,including Dahongtian(DP),Jingpitian(JP),Luyudan(LP),and Tianhonngdan(TP),were investigated via gas chromatography-mass spectrometry(GC-MS)and gas chromatography-olfactometry(GC-O)analyses.A total of 43 volatile compounds were identified by using GC-MS.Among these compounds,16 were considered as potential aroma-active compounds as detected by GC-O.These compounds belonged to the classes of terpinenes,alcohols,and aldehydes.Eleven volatile compounds were defined as the main contributors to the overall aroma of pomegranate juice due to their high odor activity values(OAVs≥1).Aroma recombination and omission tests confirmed thatβ-myrcene,1-hexanol,and(Z)-3-hexen-1-ol were the key aroma compounds,and limonene,1-octen-3-ol,linalool,and hexanal were important aroma-active compounds in DP samples.

Sensory-directed flavor analysis of key odorants compounds development of French fries and oils in the break-in,optimum and degrading frying stage

The flavor is a decisive sensory characteristic that determines the popularity of French fries(FFs).During high-oleic rapeseed oil(RO)frying,the flavor development of FFs showed three noticeable stages including break-in(3.5%-7.5%of total polar compounds(TPC)),optimum(7.5%-22.18%of TPC),and degrading stages(above 22.18%of TPC).Further,in order to distinguish the key aroma compounds in each stage,the FFs prepared in RO at TPC of 3.5%(FF4),14.5%(FF15),and 26.96%(FF27)and their relevant oils(RO4,RO15,RO27)were selected for sensory-directed analysis.The results revealed that the FF4 had low contents of(E,E)-2,4-decadienal(deep-fried odor)which also caused lower sensory score in FF4 sample.The higher contents of(E,E)-2,4-decadienal in FF15 induced its higher deep-fried odor.The FF27 had higher hexanoic acid(sweaty odor),heptanoic acid,nonanoic acid,benzene acetaldehyde(stale odor),and trans-4,5-epoxy-(E)-2-decenal(metallic odor)compared with FF4 and FF15,thus leading to the undesirable flavor of FF27.Moreover,the decrease of 2,5-dimethylpyrazine and 2-ethyl-6-methyl-pyrazine in FF27 induced the lower roasty flavor,which may also lead to the decline of the sensory score.Similarly,the higher contents of(E)-2-undecenal,hexanoic acid,heptanoic acid,and nonanoic acid in RO27 lead to increase its rancid score and thus lower the sensory score.

Study on the Antibacterial and Deodorization Effect of 4,4-Dichloro-2-Hydroxydiphenyl Ether in Laundry Gel Beads

In the formulation development of laundry gel beads,4,4-dichloro-2-hydroxydiphenyl ether(HP-100)was used as a bacteriostatic agent,and the effect of HP-100 dosage on the bacteriostatic rate of laundry gel bead samples with different formulation systems was examined by the suspension quantification method;the long-lasting bacteriostatic performance of laundry gel bead samples added with HP-100 was investigated by the absorption method for evaluating the antimicrobial performance of textiles;the effect of HP-100 on the odor control of laundry gel bead samples was investigated by filling out surveys and questionnaires using the actual measurement method.Questionnaire was used to investigate the effect of HP-100 on odor control.The test results showed that the antibacterial rate of the two laundry gel samples against S.aureus increased with the increase of HP-100 dosage,and the antibacterial rate of Formula 1 reached 99.9%when the dosage of HP-100 was 0.3%;the antibacterial rate of cotton cloth washed with the laundry gel sample of Formula 1+0.3%HP-100 was more than 50%after 24 h,and still had the antibacterial effect;the antibacterial rate of cotton cloth washed with the sample of laundry gel with HP-100 was more than 50%after 24 h,and still had the antibacterial effect;the antibacterial effect of the sample with HP-100 was more than 50%after 24 h,and still had the antibacterial effect.The fabrics washed with HP-100 added laundry gel beads had better odor control than those treated with laundry gel beads without HP-100,and the addition of HP-100 to laundry gel beads could have antibacterial and deodorizing effects.

Nurse odor perception in various Japanese hospital settings

Because unpleasant hospital odors affect the nursing environment,we investigated nurses'perceptions of the odors of various hospital settings:hospital rooms,nurse stations,and human waste disposal rooms to discard the urine,stools and diapers.A questionnaire based on the Japanese Ministry of the Environment's guidelines on odor index regulation was used to assess nurses'perceptions of odor intensity,comfort,tolerability,and description in the aforementioned settings.Questionnaires were distributed to nursing department directors at three Japanese hospitals,who then disseminated the questionnaires to nursing staff.Of the 1,151 questionnaires distributed,496 nurses participated.Human waste disposal rooms had greater odor intensity and were perceived as more uncomfortable than the other settings.Unpleasant odors in disposal rooms,hospital rooms,and nurse stations were rated as slightly intolerable in comparison.Hospital and disposal rooms were mainly described as having a“pungent odor such as of urine and stool.”In contrast,nurse stations were described as having other unpleasant odors,such as chemical,human-body-related,or sewage-like odors.Given that nurses spend much of their time in hospital rooms and nurse stations,odor management in these two settings would likely improve nurses'working conditions at hospitals.Improving odors at nurse stations is feasible.Such improvements could have indirect effects on nurse turnover and burnout.

Improving emulsion odor in cold rolling production

This paper describes the formation mechanism and mode of the emulsion odor of the cold rolling process,and introduces the relevant environmental regulations and methods used to measure the emulsion odor.Studies were conducted with respect to these issues.The technical measures used to minimize the emulsion odor,particularly the adjustment of the chemical formula of the cold rolling emulsion,are illustrated in detail.The study results have been successfully applied in cold rolling production,and a significant reduction in the emulsion odor is achieved.

Structure,Binding Characteristics,and 3D Model Prediction of a Newly Identified Odorant-Binding Protein from the Cotton Bollworm,Helicoverpa armigera (Hübner)

The full-length sequence of the odorant binding protein 5 gene,HarmOBP5,was obtained from an antennae cDNA library of cotton bollworm,Helicoverpa armigera （Hübner）.The cDNA contains a 444 bp open reading frame,encoding a protein with 147 amino acids,namely HarmOBP5.HarmOBP5 was expressed in Escherichia coli and the recombinant protein was purified by affinity chromatography.SDS-PAGE and Western blot analysis demonstrated that the purified protein can be used for further investigation of its binding characteristics.Competitive binding assays with 113 odorant chemicals indicated that HarmOBP5 has strong affinity to some special plant volatiles,including （E）-β-farnesene,ethyl butyrate,ethyl heptanoate,and acetic acid 2-methylbutyl ester.Based on three-dimensional （3D） model of AaegOBP1 from Aedes aegypti,a 3D model of HarmOBP5 was predicted.The model revealed that some key binding residues in HarmOBP5 may play important roles in odorant perception of H.armigera.This study provides clues for better understanding physiological functions of OBPs in H.armigera and other insects.

Advanced oxidation technology for H_2S odor gas using non-thermal plasma

Non-thermal plasma technology is a new type of odor treatment processing.We deal with H2Sfrom waste gas emission using non-thermal plasma generated by dielectric barrier discharge.On the basis of two criteria,removal efficiency and absolute removal amount,we deeply investigate the changes in electrical parameters and process parameters,and the reaction process of the influence of ozone on H2S gas removal.The experimental results show that H2S removal efficiency is proportional to the voltage,frequency,power,residence time and energy efficiency,while it is inversely proportional to the initial concentration of H2S gas,and ozone concentration.This study lays the foundations of non-thermal plasma technology for further commercial application.

Effect of adding Lactobacillus plantarum and soluble carbohydrates to swine manure on odorous compounds, chemical composition and indigenous flora

Manure odor, which results in the increasing complaints and lawsuits, has increased the tension among swine producers and surrounding residents. The effects of Lactobacillus plantarum and different rates of soluble carbohydrates additions to swine manure on odorous compounds, chemical compounds and indigenous flora were evaluated. Additions were calculated on dried manure weight basis. Variables monitored included ammonia （NH3）, hydrogen sulfide （H2S）, odor offensiveness, pH, ammonium nitrogen（NH4^＋-N）, volatile fatty acids （VFAs）, urease and indigenous flora. The results indicated that the combination of L. plantarum and soluble carbohydrates dramatically reduced manure pH. Lower pH resulted in the reduction of NH3 volatilization （34.6%-92.4%, P〈0.01）, the increases of H2S （P〈 0.05） and NH4^＋-N （5.3%-17.5%, P〈0.05）. In addition, L. plantarum and soluble carbohydrates additions significantly reduced odor offensiveness, those VFAs related to malodor indicators（valeric acids, 12.3%-47.7%, P〈 0.05; iso-valeric, 3.5%-23.8%） and the main microorganisms responsible for odor production, with the number of Eubacteria in swine manure reducing by 4.9%, 11.6%, 17.4%, 34.1% and 32.2% respectively.

A Learning Particle Swarm Optimization Algorithm for Odor Source Localization

This paper is concerned with the problem of odor source localization using multi-robot system. A learning particle swarm optimization algorithm, which can coordinate a multi-robot system to locate the odor source, is proposed. First, in order to develop the proposed algorithm, a source probability map for a robot is built and updated by using concentration magnitude information, wind information, and swarm information. Based on the source probability map, the new position of the robot can be generated. Second, a distributed coordination architecture, by which the proposed algorithm can run on the multi-robot system, is designed. Specifically, the proposed algorithm is used on the group level to generate a new position for the robot. A consensus algorithm is then adopted on the robot level in order to control the robot to move from the current position to the new position. Finally, the effectiveness of the proposed algorithm is illustrated for the odor source localization problem.

A conserved odorant receptor identified from antennal transcriptome of Megoura crassicauda that specifically responds to cis-jasmone

Herbivore-induced plant volatiles(HIPVs)play a key role in the interactions between plants and herbivorous insects,as HIPVs can promote or deter herbivorous insects’behavior.While aphids are common and serious phloem-feeding pests in farmland ecosystems,little is known about how aphids use their sensitive olfactory system to detect HIPVs.In this study,the antennal transcriptomes of the aphid species Megoura crassicauda were sequenced,and expression level analyses of M.crassicauda odorant receptors(ORs)were carried out.To investigate the chemoreception mechanisms that M.crassicauda uses to detect HIPVs,we performed in vitro functional studies of the ORs using 11 HIPVs reported to be released by aphid-infested plants.In total,54 candidate chemosensory genes were identified,among which 20 genes were ORs.McraOR20 and McraOR43 were selected for further functional characterization because their homologs in aphids were quite conserved and their expression levels in antennae of M.crassicauda were relatively high.The results showed that McraOR20 specifically detected cis-jasmone,as did its ortholog ApisOR20 from the pea aphid Acyrthosiphon pisum,while McraOR43 did not respond to any of the HIPV chemicals that were tested.This study characterized the ability of the homologous OR20 receptors in the two aphid species to detect HIPV cis-jasmone,and provides a candidate olfactory target for mediating aphid behaviors.

Orientation of larval and juvenile horseshoe crabs Limulus polyphemus to visual cues: Effects of chemical odors

Adult horseshoe crabs Limulus polyphemus have long served as models for the study of vision in marine arthropods. Yet, little is known about the ability of early life history stages to detect and respond to visual cues. We examined the visually directed movements of larvae and first stage juveniles to horizons containing dark visual targets of different sizes. The study tested the hypotheses that （1） larval and juvenile crabs can detect and respond to visual targets and （2） the direction of orientation varies with the presence of chemical cues associated with settlement habitats. Orientation of larval and juvenile crabs to rectangles subtending angles from 30--330~ was tested in a circular arena containing water that either lacked estuarine chemical cues （offshore water） or contained odors from aquatic vegetation or known predators. In the absence of chemical odors, larvae oriented toward and juveniles moved away from dark horizons subtending angles 〉 60~. When placed in water containing chemical odors from potential nursery habitats, including the seagrasses Halodule wrightii and Syringodium filiforme, crabs reversed their direction of orientation relative to their responses in offshore water. Odors from two known predators, the mummichug Fundulus grandis and blue crab Callinectes sapidus, had no affect on the orientation of larvae. Yet, juveniles responded to both odors by moving toward the visual target. Results support the hypothesis that the visual orientation of larval and juvenile horseshoe crabs changes upon exposure to habitat and predator cues and that the direction of the response undergoes an ontogenetic shift following metamorphosis

Pollution control of urban black-odor water bodies

On the basis of on-the-spot investigation, the causes of urban black-odor water bodies and the problems existing in the treatment are analyzed, and the control techniques and management countermeasures for black-odor water bodies were put forward. The countermeasures include: treating from both the roots and the symptoms and combining multiple technologies; comprehensively managing and improve the monitoring systems; coordinating functions and implementing long-term management; opening information and innovating supervision platform; coordinating advance and promoting the construction of sponge city; diversified financing to form the market-oriented model of water pollution control.

Ligand-binding properties of three odorant-binding proteins of the diamondback moth Plutella xylostella

Strategies for insect population control are currently targeting chemical communication at the molecular level. The diamondback moth Plutella xylostella represents one of the most serious pests in agriculture, however detailed information on the proteins mediating olfaction in this species is still poor. This species is endowed with a repertoire of a large number of olfactory receptors and odorant binding proteins（OBPs）. As a contribution to map the specificities of these chemical sensors in the moth and eventually unrave l the complexity of chemodetection, we have measured the affinities of three selected OBPs to a series of potential odorants. Three proteins are highly divergent in their amino acid sequences and show markedly different expression profiles. In fact, PxylOBP3 is exclusively expressed in the antennae of both sexes, PxylOBP9 is male specific and present only in antennae and reproductive organs, while PxylOBP19, an unusual OBP with nine cysteines, is ubiquitously present in all the organs examined. Such expression pattern suggests that the last two proteins may be involved in non-chemosensory functions. Despite such differences, the three OBPs exhibit similar binding spectra, together with high selectivity. Among the 26 natural compounds tested, only two proved to be good ligands, retinol and coniferyl aldehyde. This second compound is particularly interesting being part of the chemical pathway leading to regeneration of lignin, one of the defense strategies of the plant against insect attack, and might find applications as a repellent for P. xylostella and other pests.

Studies on Silicon-Containing Fragrance Raw Materials( Ⅱ )——Syntheses and Odors of 4-Trimethylsilylcyclohex-3-enol and 4-Trimethylsilylcyclohexanol Derivatives

1-Substituted- 4-trimethylsilylcyclohex- 3-enol and 1-substituted- 4-trimetnylsilyl-cyclohexanol, 4-trimethylsilylcyclohex-3-enol and 4-trimethylsilylcyclohexanol, and some of their esters and carbon counterparts were synthesized. Structures of the nineteen new compounds were determined by 1H NMR, IR and MS. Their odors are evaluated.

Age Structure of Two Species of Odorous Frogs(Odorrana margaretae and Odorrana grahami)

Variation in age structure and body size benefits are identified to understand the evolution of life history.Here,we estimated the age structure and body size of two species of odorous frogs(Odorrana margaretae and Odorrana grahami)by using skeletochronology.The ages at sexual maturity of O.grahami and O.margaretae in both sexes were 1 and 2 years,respectively.For both sexes,the maximum age observed in O.margaretae was six years.For O.grahami,the maximum age observed in males and females were 4 and 5 years,respectively.Males and females did not differ in mean age in the two species.The average body size of both species considerably differed between sexes,with females being larger than males.The body size of females was also larger than that of males when the effect of age was removed.We also found positive correlations between body size and age within each sex in O.margaretae,but only for female in O.grahami.The female-biased sexual size dimorphism of the two species suggested that fecundity selection for larger female size may increase the reproductive output.

ODOR DISCRIMINATION BY MITRAL CELLS IN RAT OLFACTORY BULB USING MICROWIRE ARRAY RECORDING

Response features of mitral cells in the olfactory bulb were examined using principal component analysis to determine whether they contain information about odorant stimuli.Using microwire electrode array to record from the olfactory bulb in freely breathing anesthetized rats,we recorded responses of different mitral cells to saturated vapor of anisole(1 M),carvone(1 M),isobutanol(1 M),citral(1 M)and isoamyl actate(1 M).The responses of single mitral cells to the same odorant varied over time.The response profiles showed similarity during certain amount of period,which indicated that the response was not only depended on odor itself but also associated with context.Furthermore,the responses of single mitral cell to different odorants were observed with difference in firing rate.In order to recognize different odorant stimuli,we apply four cells as a sensing group for classification using principal component analysis.Features of each cell’s response describing both temporal and frequency characteristics were selected.The results showed that five different single molecular odorants can be distinguished from each other.These data suggest that action potentials of mitral cells may play a role in odor coding.