Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
1.
Nano Lett ; 23(22): 10466-10472, 2023 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-37930772

RESUMEN

Nitrogenase MoFe protein can be coupled with CdS nanocrystals (NCs) to enable photocatalytic N2 reduction. The nature of interactions that support complex formation is of paramount importance in intermolecular electron transfer that supports catalysis. In this work we have employed microscale thermophoresis to examine binding interactions between 3-mercaptopropionate capped CdS quantum dots (QDs) and MoFe protein over a range of QD diameters (3.4-4.3 nm). The results indicate that the interactions are largely electrostatic, with the strength of interactions similar to that observed for the physiological electron donor. In addition, the strength of interactions is sensitive to the QD diameter, and the binding interactions are significantly stronger for QDs with smaller diameters. The ability to quantitatively assess NC protein interactions in biohybrid systems supports strategies for understanding properties and reaction parameters that are important for obtaining optimal rates of catalysis in biohybrid systems.


Asunto(s)
Molibdoferredoxina , Puntos Cuánticos , Molibdoferredoxina/química , Molibdoferredoxina/metabolismo , Electricidad Estática , Nitrogenasa/química , Nitrogenasa/metabolismo , Transporte de Electrón
2.
J Am Chem Soc ; 145(39): 21165-21169, 2023 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-37729189

RESUMEN

A critical step in the mechanism of N2 reduction to 2NH3 catalyzed by the enzyme nitrogenase is the reaction of the four-electron/four-proton reduced intermediate state of the active-site FeMo-cofactor (E4(4H)). This state is a junction in the catalytic mechanism, either relaxing by the reaction of a metal bound Fe-hydride with a proton forming H2 or going forward with N2 binding coupled to the reductive elimination (re) of two Fe-hydrides as H2 to form the E4(2N2H) state. E4(2N2H) can relax to E4(4H) by the oxidative addition (oa) of H2 and release of N2 or can be further reduced in a series of catalytic steps to release 2NH3. If the H2 re/oa mechanism is correct, it requires that oa of H2 be associative with E4(2N2H). In this report, we have taken advantage of CdS quantum dots in complex with MoFe protein to achieve photodriven electron delivery in the frozen state, with cryo-annealing in the dark, to reveal details of the E-state species and to test the stability of E4(2N2H). Illumination of frozen CdS:MoFe protein complexes led to formation of a population of reduced intermediates. Electron paramagnetic resonance spectroscopy identified E-state signals including E2 and E4(2N2H), as well as signals suggesting the formation of E6 or E8. It is shown that in the frozen state when pN2 is much greater than pH2, the E4(2N2H) state is kinetically stable, with very limited forward or reverse reaction rates. These results establish that the oa of H2 to the E4(2N2H) state follows an associative reaction mechanism.

3.
J Exp Biol ; 226(2)2023 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-36354120

RESUMEN

Many animals locate food, mates and territories by following plumes of attractive odors. There are clear differences in the structure of this plume-tracking behavior depending on whether an animal is flying, swimming, walking or crawling. These differences could arise from different control rules used by the central nervous system during these different modes of locomotion or one set of rules interacting with the different environments while walking on the surface versus flying or swimming. Flow speeds and turbulence that characterize the environments where walking and flying insects track plumes may alter the structure of odor plumes in an environment-specific way that results in the same control rules generating behaviors that appear quite different. We tested these ideas by challenging walking male cockroaches, Periplaneta americana, and flying male moths, Manduca sexta, to track plumes of their species' sex pheromones in low wind speeds characteristic of cockroach experimental environments, higher wind speeds characteristic of moth experimental environments, and conditions ranging from low to high turbulence. Introducing a turbulence-generating structure into the flow significantly improved the flying plume tracker's ability to locate the odor source, and changed the structure of the behavior of both flying and walking plume trackers. Our results support the idea that plume trackers moving slowly along the substrate may use the spatial distribution of odor, while faster moving flying plume trackers may use the timing of odor encounters to steer to locate the source.


Asunto(s)
Mariposas Nocturnas , Atractivos Sexuales , Animales , Masculino , Odorantes , Insectos , Mariposas Nocturnas/fisiología , Caminata , Vuelo Animal/fisiología
4.
J Chem Phys ; 159(23)2023 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-38117020

RESUMEN

The biological reduction of N2 to ammonia requires the ATP-dependent, sequential delivery of electrons from the Fe protein to the MoFe protein of nitrogenase. It has been demonstrated that CdS nanocrystals can replace the Fe protein to deliver photoexcited electrons to the MoFe protein. Herein, light-activated electron delivery within the CdS:MoFe protein complex was achieved in the frozen state, revealing that all the electron paramagnetic resonance (EPR) active E-state intermediates in the catalytic cycle can be trapped and characterized by EPR spectroscopy. Prior to illumination, the CdS:MoFe protein complex EPR spectrum was composed of a S = 3/2 rhombic signal (g = 4.33, 3.63, and 2.01) consistent with the FeMo-cofactor in the resting state, E0. Illumination for sequential 1-h periods at 233 K under 1 atm of N2 led to a cumulative attenuation of E0 by 75%. This coincided with the appearance of S = 3/2 and S = 1/2 signals assigned to two-electron (E2) and four-electron (E4) reduced states of the FeMo-cofactor, together with additional S = 1/2 signals consistent with the formation of E6 and E8 states. Simulations of EPR spectra allowed quantification of the different E-state populations, along with mapping of these populations onto the Lowe-Thorneley kinetic scheme. The outcome of this work demonstrates that the photochemical delivery of electrons to the MoFe protein can be used to populate all of the EPR active E-state intermediates of the nitrogenase MoFe protein cycle.


Asunto(s)
Azotobacter vinelandii , Puntos Cuánticos , Molibdoferredoxina/química , Molibdoferredoxina/metabolismo , Temperatura , Oxidación-Reducción , Nitrogenasa/química , Nitrogenasa/metabolismo , Espectroscopía de Resonancia por Spin del Electrón/métodos , Azotobacter vinelandii/metabolismo
5.
Plant Physiol ; 179(3): 1144-1158, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30630869

RESUMEN

ATP is not only an essential metabolite of cellular biochemistry but also acts as a signal in the extracellular milieu. In plants, extracellular ATP is monitored by the purinergic receptor P2K1. Recent studies have revealed that extracellular ATP acts as a damage-associated molecular pattern in plants, and its signaling through P2K1 is important for mounting an effective defense response against various pathogenic microorganisms. Biotrophic and necrotrophic pathogens attack plants using different strategies, to which plants respond accordingly with salicylate-based or jasmonate/ethylene-based defensive signaling, respectively. Interestingly, defense mediated by P2K1 is effective against pathogens of both lifestyles, raising the question of the level of interplay between extracellular ATP signaling and that of jasmonate, ethylene, and salicylate. To address this issue, we analyzed ATP-induced transcriptomes in wild-type Arabidopsis (Arabidopsis thaliana) seedlings and mutant seedlings defective in essential components in the signaling pathways of jasmonate, ethylene, and salicylate (classic defense hormones) as well as a mutant and an overexpression line of the P2K1 receptor. We found that P2K1 function is crucial for faithful ATP-induced transcriptional changes and that a subset of genes is more responsive in the P2K1 overexpression line. We also found that more than half of the ATP-responsive genes required signaling by one or more of the pathways for the classical defense hormones, with the jasmonate-based signaling being more critical than others. By contrast, the other ATP-responsive genes were unaffected by deficiencies in signaling for any of the classical defense hormones. These ATP-responsive genes were highly enriched for defense-related Gene Ontology terms. We further tested the ATP-induced genes in knockout mutants of transcription factors, demonstrating that MYCs acting downstream of the jasmonate receptor complex and calmodulin-binding transcription activators are nuclear transducers of P2K1-mediated extracellular ATP signaling.


Asunto(s)
Adenosina Trifosfato/metabolismo , Arabidopsis/metabolismo , Transcriptoma , Arabidopsis/genética , Ciclopentanos/metabolismo , Etilenos/metabolismo , Regulación de la Expresión Génica de las Plantas , Oxilipinas/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo , Salicilatos/metabolismo , Plantones/genética , Plantones/metabolismo , Transducción de Señal/genética
6.
Zoo Biol ; 39(1): 51-55, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31746026

RESUMEN

Positive reinforcement training (PRT) is associated with increases in species-typical behavior and decreases in stereotypic and abnormal behavior in participating animals. Physiological changes following PRT, for example, increases in oxytocin (OXT) and/or decreases in cortisol (CORT), may facilitate these behavioral changes. This study evaluated salivary OXT and salivary CORT concentrations in two adult male western lowland gorillas (Gorilla gorilla gorilla) following PRT with their primary animal care staff. Following PRT, no change in OXT was observed. CORT decreased in one subject following PRT. Changes in endogenous OXT are related to affiliative interactions and interact with strongly bonded conspecifics. PRT may not activate the oxytocinergic system because PRT is not a species-specific affiliative interaction and/or animal care staff are not viewed as conspecifics. Regardless, PRT may still be viewed as a positive interaction resulting in stress reduction via a decrease in CORT. Relationships are unique, thus these results only apply to these two gorillas and one animal caregiver. Larger population-level studies are needed to understand overall trends in human-animal interactions, and ultimately human-animal relationships. Further evaluation of physiological changes following human-animal interactions should be informative for understanding the human-animal relationship in zoos.


Asunto(s)
Gorilla gorilla/fisiología , Hidrocortisona/química , Oxitocina/química , Refuerzo en Psicología , Saliva/química , Crianza de Animales Domésticos , Animales , Animales de Zoológico , Conducta Animal/fisiología , Hidrocortisona/metabolismo , Masculino , Oxitocina/metabolismo
7.
J Exp Biol ; 221(Pt 21)2018 10 31.
Artículo en Inglés | MEDLINE | ID: mdl-29967220

RESUMEN

While tracking odor plumes, male hawkmoths use optic flow cues to stabilize their flight movements with respect to their environment. We studied the responses of freely flying moths tracking odor plumes in a laboratory wind tunnel and tethered moths in an optomotor flight simulator to determine the locations on the compound eye on which critical optic flow cues are detected. In these behavioral experiments, we occluded specific regions of the compound eye and systematically examined the moths' behavior for specific deficits in optic flow processing. Freely flying moths with the dorsal half of the compound eye painted were unable to maintain stable flight and track the wind-borne odor plume. However, the plume tracking performance of moths with the ventral half of their compound eyes painted was the same as unpainted controls. In a matched set of experiments, we presented tethered moths with moving vertically oriented sinusoidal gratings and found that individuals with their eyes unpainted, ventrally painted and medially painted all responded by attempting optomotor-driven turns in the same proportion. In contrast, individuals with their compound eyes dorsally painted, laterally painted and completely painted showed no optomotor turning response. We decreased the contrast of the visual stimulus and found that this relationship was consistent down to a contrast level of 2.5%. We conclude that visual input from the dorso-lateral region of the moth's visual world is critical for successful maintenance of flight stability and that this species' visual environment must meet or exceed a contrast ratio of 2.5% to support visual flight control.


Asunto(s)
Ojo Compuesto de los Artrópodos , Manduca/fisiología , Animales , Señales (Psicología) , Vuelo Animal/fisiología , Masculino , Flujo Optico , Atractivos Sexuales , Conducta Espacial/fisiología , Campos Visuales/fisiología
8.
Zoo Biol ; 37(1): 3-15, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29315790

RESUMEN

Zoo-housed bears are prone to exhibiting stereotypic behaviors, generally considered indicators of negative welfare. We explored the effects of a variable-time feeding enrichment schedule on behavioral indicators of welfare in four bear species at Cleveland Metroparks Zoo. We distributed the diets of eight bears in one of five enrichment items, for two consecutive days each, and monitored behavior throughout the day. In Experiment 1, we compared variable-time to fixed-time presentation of enrichment over two, 10-day periods. Overall, bears performed more exploratory behavior when enriched (p < 0.0001). Furthermore, variable-time enrichment was associated with a greater increase in exploratory behavior than fixed-time enrichment when compared to baseline (p < 0.001). Both fixed-time (punadjusted <0.05, padjusted = 0.07) and variable-schedule (punadjusted <0.05, padjusted = 0.09) enrichment were also associated with similar decreases in abnormal behavior compared to baseline. For Experiment 2, we tested habituation to enrichment over 30 days using multiple items and a semi-variable presentation schedule. Again during the enrichment period, bears exhibited increased exploratory behavior (p < 0.0001) and decreased abnormal behaviors compared to baseline (punadjusted = 0.05, padjusted = 0.09). We observed no habituation during the 30-day sustained enrichment period for these behaviors. Collectively, these results suggest that daily, variable-schedule feeding enrichment, with intermittent presentation of unique enrichment items, increases behavioral indicators of positive welfare and decreases behavioral indicators of negative welfare.


Asunto(s)
Crianza de Animales Domésticos/métodos , Animales de Zoológico , Conducta Animal/fisiología , Conducta Estereotipada/fisiología , Ursidae/fisiología , Alimentación Animal , Bienestar del Animal , Animales
9.
J Exp Biol ; 218(Pt 14): 2156-65, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25987729

RESUMEN

Determining the location of a particular stimulus is often crucial to an animal's survival. One way to determine the local distribution of an odor is to make simultaneous comparisons across multiple sensors. If the sensors detect differences in the distribution of an odor in space, the animal can then steer toward the source. American cockroaches, Periplaneta americana, have 4 cm long antennae and are thought to track odor plumes using a spatial sampling strategy, comparing the amount of odor detected between these bilateral sensors. However, it is not uncommon for cockroaches to lose parts of their antennae and still track a wind-borne odor to its source. We examined whether bilateral odor input is necessary to locate an odor source in a wind-driven environment and how the loss of increasing lengths of the antennae affects odor tracking. The tracking performances of individuals with two bilaterally symmetrical antennae of decreasing length were compared with antennal length-matched individuals with one antenna. Cockroaches with one antenna were generally able to track an odor plume to its source. In fact, the performances of unilaterally antennectomized individuals were statistically identical to those of their bilaterally symmetrical counterparts when the combined length of both antennae equaled the length of the single antenna of the antennectomized individuals. This suggests that the total length of available antennae influences odor tracking performance more than any specific piece of antenna, and that they may be doing something more complex than a simple bilateral comparison between their antennae. The possibility of an antenna-topic map is discussed.


Asunto(s)
Odorantes , Periplaneta/fisiología , Atractivos Sexuales , Animales , Antenas de Artrópodos/fisiología , Conducta Animal , Lateralidad Funcional , Masculino , Movimiento , Orientación , Viento
10.
J Relig Health ; 54(2): 676-92, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25150056

RESUMEN

Chaplaincy has traditionally been considered a profession highly respectful of confidentiality. Nevertheless, given increasing professional collaboration within health and welfare contexts, plus the requirements of intervention reporting and the ease of technological data sharing, it is possible that confidentiality may be sacrificed for the sake of expediency. This exploratory review considers the literature relating to the role of chaplaincy and confidentiality that suggests a number of principles which should be considered by chaplaincy associations/organizations to ensure appropriate professional practice and the holistic health and well-being of patients/clients. Recommendations are made for the development of specific policies and procedures, confidentiality training programs and further research for developing universal protocols relating to chaplains and their handling of confidential information.


Asunto(s)
Clero/ética , Confidencialidad/ética , Religión y Medicina , Humanos , Privacidad
11.
J Appl Anim Welf Sci ; 27(3): 575-588, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38363302

RESUMEN

Cognitive biases reveal underlying affective state by indicating optimism and pessimism. This methodology may permit assessment of positive welfare in animals that have few validated positive welfare indicators, such as bears. Our goal was to validate a judgment bias test for assessing optimism in brown bears, using a touchscreen. After training the bears on a conditional discrimination, we compared responses to an ambiguous stimulus in a 2 × 2 nested design involving four experimental conditions representing presence or absence of a behind-the-scenes tour and presence or absence of a keeper training session with food reinforcement. We recorded bears' behavior during the conditions as a measure of convergent validity. Testing revealed the possibility of pessimism in the absence of reinforcement in one bear. More frustration behaviors were also observed during the no food reinforcement conditions. This is the first experimental demonstration of brown bears using a touchscreen and one of only three reports in which bears have been reported to perform a conditional discrimination. This method of assessing underlying affective state shows promise for the future.


Asunto(s)
Bienestar del Animal , Juicio , Refuerzo en Psicología , Ursidae , Ursidae/psicología , Animales , Masculino , Femenino , Conducta Animal , Optimismo/psicología , Pesimismo/psicología
12.
Bio Protoc ; 14(15): e5041, 2024 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-39131194

RESUMEN

Microscale thermophoresis (MST) is a technique used to measure the strength of molecular interactions. MST is a thermophoretic-based technique that monitors the change in fluorescence associated with the movement of fluorescent-labeled molecules in response to a temperature gradient triggered by an IR LASER. MST has advantages over other approaches for examining molecular interactions, such as isothermal titration calorimetry, nuclear magnetic resonance, biolayer interferometry, and surface plasmon resonance, requiring a small sample size that does not need to be immobilized and a high-sensitivity fluorescence detection. In addition, since the approach involves the loading of samples into capillaries that can be easily sealed, it can be adapted to analyze oxygen-sensitive samples. In this Bio-protocol, we describe the troubleshooting and optimization we have done to enable the use of MST to examine protein-protein interactions, protein-ligand interactions, and protein-nanocrystal interactions. The salient elements in the developed procedures include 1) loading and sealing capabilities in an anaerobic chamber for analysis using a NanoTemper MST located on the benchtop in air, 2) identification of the optimal reducing agents compatible with data acquisition with effective protection against trace oxygen, and 3) the optimization of data acquisition and analysis procedures. The procedures lay the groundwork to define the determinants of molecular interactions in these technically demanding systems. Key features • Established procedures for loading and sealing tubes in an anaerobic chamber for subsequent analysis. • Sodium dithionite (NaDT) could easily be substituted with one electron-reduced 1,1'-bis(3-sulfonatopropyl)-4,4'-bipyridinium [(SPr)2V•] to perform sensitive biophysical assays on oxygen-sensitive proteins like the MoFe protein. • Established MST as an experimental tool to quantify binding affinities in novel enzyme-quantum dot biohybrid complexes that are extremely oxygen-sensitive.

13.
Artículo en Inglés | MEDLINE | ID: mdl-24081678

RESUMEN

Males of the hawkmoth, Manduca sexta, track wind-borne plumes of female sex pheromone by flying upwind, while continuously turning from side-to-side and changing altitude. Their characteristic "zigzagging" trajectory has long been thought to result from the interaction of two mechanisms, an odor-modulated orientation to wind and a built-in central nervous system turning program. An interesting and as of yet unanswered question about this tracking behavior is how the cross-section of an odor plume or its clean-air "edges" affects moths' odor tracking behavior. This study attempts to address this question by video recording and analyzing the behavior of freely flying M. sexta males tracking plumes from pheromone sources of different lengths and orientations with equal odor concentration per unit area. Our results showed that moths generated significantly wider tracks in wide plumes from the longest horizontally-oriented sources as compared to narrower point-source plumes, but had relatively unaltered tracks when orienting to plumes from the same length sources oriented vertically. This suggests that in addition to wind and the presence of pheromones, the area of the plume's cross section or its edges may also play an important role in the plume tracking mechanisms of M. sexta.


Asunto(s)
Vuelo Animal/efectos de los fármacos , Manduca/fisiología , Odorantes , Orientación/efectos de los fármacos , Atractivos Sexuales/farmacología , Análisis de Varianza , Animales , Antenas de Artrópodos/efectos de los fármacos , Femenino , Vuelo Animal/fisiología , Masculino , Orientación/fisiología , Atractivos Sexuales/metabolismo , Factores de Tiempo
14.
Biomimetics (Basel) ; 8(8)2023 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-38132532

RESUMEN

Odor-guided navigation is fundamental to the survival and reproductive success of many flying insects. Despite its biological importance, the mechanics of how insects sense and interpret odor plumes in the presence of complex flow fields remain poorly understood. This study employs numerical simulations to investigate the influence of turbulence, wingbeat-induced flow, and Schmidt number on the structure and perception of odor plumes by flying insects. Using an in-house computational fluid dynamics solver based on the immersed-boundary method, we solve the three-dimensional Navier-Stokes equations to model the flow field. The solver is coupled with the equations of motion for passive flapping wings to emulate wingbeat-induced flow. The odor landscape is then determined by solving the odor advection-diffusion equation. By employing a synthetic isotropic turbulence generator, we introduce turbulence into the flow field to examine its impact on odor plume structures. Our findings reveal that both turbulence and wingbeat-induced flow substantially affect odor plume characteristics. Turbulence introduces fluctuations and perturbations in the plume, while wingbeat-induced flow draws the odorant closer to the insect's antennae. Moreover, we demonstrate that the Schmidt number, which affects odorant diffusivity, plays a significant role in odor detectability. Specifically, at high Schmidt numbers, larger fluctuations in odor sensitivity are observed, which may be exploited by insects to differentiate between various odorant volatiles emanating from the same source. This study provides new insights into the complex interplay between fluid dynamics and sensory biology and behavior, enhancing our understanding of how flying insects successfully navigate using olfactory cues in turbulent environments.

15.
Primates ; 64(1): 65-77, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36472720

RESUMEN

Evaluating how primates in human care function within their social environment is important for understanding and optimizing their management and welfare. The neuroendocrine hormone oxytocin is associated with affiliation and bonding, suggesting it can be used to evaluate the affiliative nature of social groupings. When paired with cortisol concentrations, social stressors can simultaneously be assessed, providing a more complete picture of primate social environments than if measuring either hormone independently. Here, we measured both oxytocin and cortisol in urine within a large subset of male western lowland gorillas (Gorilla gorilla gorilla; n = 71) living in North American zoos. Both endocrine measures were compared between social group types, with an emphasis on comparing bachelor and mixed-sex groupings to understand how these broad management practices affect male gorillas in zoos. Oxytocin concentrations were greater in bachelor group males than mixed-sex group males and singly housed males, providing physiological evidence that males in bachelor groups form comparatively stronger affiliative relationships than males in other group types. Cortisol concentrations did not differ between bachelor and mixed-sex group males and males in both group types had lower cortisol concentrations than singly housed males. These results indicate that males are similarly capable of coping with group-specific social stressors, and single management may expose males to additional stressors for which further study is needed. These data contribute to a larger body of research highlighting the value of bachelor groups from both a population management and individual welfare perspective.


Asunto(s)
Gorilla gorilla , Hidrocortisona , Oxitocina , Animales , Masculino , Animales de Zoológico/fisiología , Gorilla gorilla/fisiología , Hidrocortisona/orina , América del Norte , Oxitocina/orina
16.
Front Plant Sci ; 14: 1229620, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37662178

RESUMEN

The bacterial pathogen Candidatus Liberibacter asiaticus (CLas) is the causal agent of citrus greening disease. This unusual plant pathogenic bacterium also infects its psyllid host, the Asian citrus psyllid (ACP). To investigate gene expression profiles with a focus on genes involved in infection and circulation within the psyllid host of CLas, RNA-seq libraries were constructed from CLas-infected and CLas-free ACP representing the five different developmental stages, namely, nymphal instars 1-2, 3, and 4-5, and teneral and mature adults. The Gbp paired-end reads (296) representing the transcriptional landscape of ACP across all life stages and the official gene set (OGSv3) were annotated based on the chromosomal-length v3 reference genome and used for de novo transcript discovery resulting in 25,410 genes with 124,177 isoforms. Differential expression analysis across all ACP developmental stages revealed instar-specific responses to CLas infection, with greater overall responses by nymphal instars, compared to mature adults. More genes were over-or under-expressed in the 4-5th nymphal instars and young (teneral) adults than in instars 1-3, or mature adults, indicating that late immature instars and young maturing adults were highly responsive to CLas infection. Genes identified with potential for direct or indirect involvement in the ACP-CLas circulative, propagative transmission pathway were predominantly responsive during early invasion and infection processes and included canonical cytoskeletal remodeling and endo-exocytosis pathway genes. Genes with predicted functions in defense, development, and immunity exhibited the greatest responsiveness to CLas infection. These results shed new light on ACP-CLas interactions essential for pathogenesis of the psyllid host, some that share striking similarities with effector protein-animal host mechanisms reported for other culturable and/or fastidious bacterial- or viral- host pathosystems.

17.
J Exp Biol ; 214(Pt 24): 4121-32, 2011 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-22116754

RESUMEN

The walking paths of male cockroaches, Periplaneta americana, tracking point-source plumes of female pheromone often appear similar in structure to those observed from flying male moths. Flying moths use visual-flow-field feedback of their movements to control steering and speed over the ground and to detect the wind speed and direction while tracking plumes of odors. Walking insects are also known to use flow field cues to steer their trajectories. Can the upwind steering we observe in plume-tracking walking male cockroaches be explained by visual-flow-field feedback, as in flying moths? To answer this question, we experimentally occluded the compound eyes and ocelli of virgin P. americana males, separately and in combination, and challenged them with different wind and odor environments in our laboratory wind tunnel. They were observed responding to: (1) still air and no odor, (2) wind and no odor, (3) a wind-borne point-source pheromone plume and (4) a wide pheromone plume in wind. If walking cockroaches require visual cues to control their steering with respect to their environment, we would expect their tracks to be less directed and more variable if they cannot see. Instead, we found few statistically significant differences among behaviors exhibited by intact control cockroaches or those with their eyes occluded, under any of our environmental conditions. Working towards our goal of a comprehensive understanding of chemo-orientation in insects, we then challenged flying and walking male moths to track pheromone plumes with and without visual feedback. Neither walking nor flying moths performed as well as walking cockroaches when there was no visual information available.


Asunto(s)
Señales (Psicología) , Mariposas Nocturnas/fisiología , Periplaneta/fisiología , Feromonas/metabolismo , Animales , Femenino , Vuelo Animal , Masculino , Odorantes/análisis , Orientación , Conducta Sexual Animal , Percepción Espacial , Caminata
18.
Biol Cybern ; 104(6): 351-67, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21728014

RESUMEN

We develop a method that allows a flyer to estimate its own motion (egomotion), the wind velocity, ground slope, and flight height using only inputs from onboard optic flow and air velocity sensors. Our artificial algorithm demonstrates how it could be possible for flying insects to determine their absolute egomotion using their available sensors, namely their eyes and wind sensitive hairs and antennae. Although many behaviors can be performed by only knowing the direction of travel, behavioral experiments indicate that odor tracking insects are able to estimate the wind direction and control their absolute egomotion (i.e., groundspeed). The egomotion estimation method that we have developed, which we call the opto-aeronautic algorithm, is tested in a variety of wind and ground slope conditions using a video recorded flight of a moth tracking a pheromone plume. Over all test cases that we examined, the algorithm achieved a mean absolute error in height of 7% or less. Furthermore, our algorithm is suitable for the navigation of aerial vehicles in environments where signals from the Global Positioning System are unavailable.


Asunto(s)
Algoritmos , Simulación por Computador , Vuelo Animal , Insectos/fisiología , Modelos Biológicos , Modelos Teóricos , Percepción de Movimiento/fisiología , Aeronaves/instrumentación , Animales , Masculino , Mariposas Nocturnas/fisiología , Feromonas , Reología , Células Receptoras Sensoriales/fisiología , Grabación en Video , Viento
19.
Artículo en Inglés | MEDLINE | ID: mdl-19018543

RESUMEN

We studied the relationship between vertical and lateral movements during free flight odor plume tracking by male moths, Manduca sexta, in a wind tunnel with the "horizon" set at different altitudes. Three-dimensional recordings revealed that the plume tracking males generated roughly equivalent movements vertically and laterally regardless of horizon height. We hypothesized that the moths' tracks would be narrower in the vertical plane when they were presented with visual patterns on the tunnel's side walls. Instead, we discovered that their tracks tended to be wider in the horizontal plane. Anecdotal observations of other moth species describe plume tracking flight in three dimensions as "spiraling", suggesting a specific predictable relationship between vertical and lateral movements. However, we found that the relative phase, frequency, and amplitude of the vertical versus lateral movements vary on a maneuver-by-maneuver basis with no predictable temporal or spatial relationship. Our analyses suggest that a moth's trajectory in 3D can best be described as progressing upwind toward the source while cutting through the plume from all directions with loops of different radii. This is a more precise description than the terms "zigzagging" and "counter-turning" which were derived from 2D analyses of this behavior.


Asunto(s)
Comunicación Animal , Vuelo Animal/fisiología , Feromonas/farmacología , Conducta Sexual Animal/efectos de los fármacos , Olfato/fisiología , Viento , Análisis de Varianza , Animales , Masculino , Manduca/fisiología , Movimiento/efectos de los fármacos , Movimiento/fisiología , Orientación/efectos de los fármacos , Orientación/fisiología , Conducta Sexual Animal/fisiología
20.
Primates ; 59(6): 499-515, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30030689

RESUMEN

The neuroendocrine hormone oxytocin, which is an important physiological driver of social behavior and bonding, is increasingly being measured in conjunction with behavior to better understand primate sociality. To date no data are available on oxytocin concentrations within the genus Gorilla; however, as a result of their close genetic relatedness to humans, and tolerance-based social system, Gorilla represents an important group of study. The purpose of this study was to validate the measurement of urinary and salivary oxytocin in western lowland gorillas (Gorilla gorilla gorilla) to help facilitate future study of the interaction between oxytocin and behavior within the subspecies. The primary validation procedure was an intranasal challenge. Elevated oxytocin concentrations were observed in saliva samples taken 15-120 min post challenge. Urine levels remained within baseline range approximately 30 and 90 min following the challenge; however, elevated levels were observed 24 h post challenge. No diurnal variation was found in salivary samples taken at regular intervals throughout the day; however, morning urine samples had higher concentrations than afternoon samples. In addition, samples were collected opportunistically following three social events: play, breeding, and the death of a conspecific. Following the play bouts, salivary oxytocin was almost three times greater than baseline. Salivary oxytocin was also significantly higher 15 min post breeding compared to match-control samples. Following the death of a conspecific, the group mate's urinary oxytocin concentrations decreased by half compared to a baseline period when the group was intact. This study provides a biological validation of the measurement of urinary and salivary oxytocin in western lowland gorillas. These results suggest that urinary oxytocin measurements are suitable for establishing baseline levels, as they represent the build up of the previous day's concentrations, and salivary oxytocin measurements are suitable for assessing changes following specific events.


Asunto(s)
Gorilla gorilla/fisiología , Técnicas para Inmunoenzimas/veterinaria , Oxitocina/análisis , Oxitocina/orina , Saliva/química , Animales , Animales de Zoológico , Conducta Animal , Femenino , Gorilla gorilla/orina , Técnicas para Inmunoenzimas/instrumentación , Técnicas para Inmunoenzimas/métodos , Masculino , Juego de Reactivos para Diagnóstico , Sensibilidad y Especificidad
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA