scholarly journals Mutagenesis of orco impairs foraging but not oviposition in the hawkmoth Manduca sexta

2019 ◽  
Author(s):  
Richard A. Fandino ◽  
Alexander Haverkamp ◽  
Sonja Bisch-Knaden ◽  
Jin Zhang ◽  
Sascha Bucks ◽  
...  

AbstractPlant volatile detection through olfaction plays a crucial role in insect behaviors. In vivo, the odorant receptor co-receptor orco is an obligatory component for the function of odorant receptors (ORs), a major receptor family involved in insect olfaction. We used CRISPR-Cas9 targeted mutagenesis to knock-out (KO) orco in a neurophysiological model species, the hawkmoth Manduca sexta. M. sexta and its host, the Sacred Datura (Datura wrightii) share a model insect-plant relationship based on mutualistic and antagonistic life history traits. D. wrightii is the innately preferred nectar-source and oviposition host for M. sexta. Hence, the hawkmoth is an important pollinator while the M. sexta larvae are specialized herbivores of the plant. We generated an orco KO through CRISPR-Cas9 to test the consequences of a loss of OR-mediated olfaction in this insect-plant relationship. Neurophysiological characterization revealed severely reduced antennal and antennal lobe responses to representative odorants emitted by D. wrightii. In a wind-tunnel setting with a flowering plant, orco KO hawkmoths showed disrupted flight orientation and an ablated proboscis extension response to the natural stimulus. However, when testing the oviposition behavior of mated females encountering a non-flowering plant, there was no difference between orco KO and wild type females regarding upwind flight orientation and number of eggs laid. Overall, OR-mediated olfaction is essential for foraging and pollination behaviors, but plant-seeking and oviposition behaviors appear largely unaffected.Significance statementInsects detect plant volatiles mainly through the expression of ORs and IRs on the antennal olfactory sensory neurons (OSNs). In vivo, Orco is an obligate partner for OR, but not IR function and ORs mediate a vast spectrum of olfactory perception. We applied CRISPR-Cas9 in M. sexta to mutate the orco gene and determine the physiological and behavioral implication of a loss of Orco receptor function in a semi-ecological interaction with D. wrightii. We found that while behaviors related to foraging were largely disrupted, other sensory modalities outside Orco function determine the relationship between an ovipositing female and its plant host. These results have implications toward understanding the olfactory basis of insect-plant interactions shaping our ecological and agricultural landscapes.

2019 ◽  
Vol 116 (31) ◽  
pp. 15677-15685 ◽  
Author(s):  
Richard A. Fandino ◽  
Alexander Haverkamp ◽  
Sonja Bisch-Knaden ◽  
Jin Zhang ◽  
Sascha Bucks ◽  
...  

The hawkmoth Manduca sexta and one of its preferred hosts in the North American Southwest, Datura wrightii, share a model insect–plant relationship based on mutualistic and antagonistic life-history traits. D. wrightii is the innately preferred nectar source and oviposition host for M. sexta. Hence, the hawkmoth is an important pollinator while the M. sexta larvae are specialized herbivores of the plant. Olfactory detection of plant volatiles plays a crucial role in the behavior of the hawkmoth. In vivo, the odorant receptor coreceptor (Orco) is an obligatory component for the function of odorant receptors (ORs), a major receptor family involved in insect olfaction. We used CRISPR-Cas9 targeted mutagenesis to knock out (KO) the MsexOrco gene to test the consequences of a loss of OR-mediated olfaction in an insect–plant relationship. Neurophysiological characterization revealed severely reduced antennal and antennal lobe responses to representative odorants emitted by D. wrightii. In a wind-tunnel setting with a flowering plant, Orco KO hawkmoths showed disrupted flight orientation and an ablated proboscis extension response to the natural stimulus. The Orco KO gravid female displayed reduced attraction toward a nonflowering plant. However, more than half of hawkmoths were able to use characteristic odor-directed flight orientation and oviposit on the host plant. Overall, OR-mediated olfaction is essential for foraging and pollination behaviors, but plant-seeking and oviposition behaviors are sustained through additional OR-independent sensory cues.


Author(s):  
Lincoln Best ◽  
Christopher J Marshall ◽  
Cody Feuerborn ◽  
Sarah Kincaid ◽  
Andony Melathopoulos ◽  
...  

The Oregon Bee Atlas is a new volunteer-led effort to characterize the bee fauna of Oregon State by collecting, preparing, and databasing native bee species and capturing plant host records. In 2018, volunteers collected 11,044 bee specimens across 33 Oregon counties, representing 179 unique bee species, and 32 unique bee genera. Specimens were collected from a total of 310 unique flowering plant genera, resulting in one of the largest state-level databases of bee-host plant interactions. Volunteers produced valuable occurrence records for species poorly known for the State, and species of conservation concern. The 2018 efforts constitute a proof-of-concept of a specimen-focused volunteer native bee survey.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Earnest Oghenesuvwe Erhirhie ◽  
Chidozie Ikegbune ◽  
Anthony Ifeanyi Okeke ◽  
Chukwunonso Chukwudike Onwuzuligbo ◽  
Ngozi Ukamaka Madubuogwu ◽  
...  

AbstractDevelopment of resistance by malaria parasites to conventional antimalarial drugs has rejuvenated the exploration of herbal medicine as alternatives. Also, the increasing rate of the use of herbal antimalarial remedies in combination with conventional antimalarial drugs (both synthetic and semi-synthetic) has inspired researchers to validate their herb-drug interaction effects. This review evaluated the interaction outcomes between herbal antimalarial drugs in combination with conventional antimalarial drugs. With the aid of electronic databases, Pubmed and Google scholar, articles related to this subject were sourced from English peer reviewed scientific journals published from 2003 to 2020. Search terms used include “antimalarial-herbal drugs interaction”, “antimalarial medicinal plant interactions with conventional antimalarial drugs”, “drug-herbal interactions, “antimalarial drugs and medicinal plants”. Synergistic, antagonistic and none effects were reported among 30 studies reviewed. Among 18 in vivo studies on P. berghei and P. yoelii nigerense infected mice model, 14 showed synergism, 3 showed antagonism and 1 involving three plants showed both effects. Among 9 in-vivo studies involving normal animal (non-infected), 2 showed antagonism, 2 showed synergism and 5 showed none-effects. Two (2) studies on human volunteers and one (1) in vitro quantitative study showed that Garcinia kola reduced plasma concentrations of quinine and halofantrine. Generally, majority of herbal antimalarial drugs showed synergistic effects with CAMDs. Vernonia amygdalina was the most studied plant compared to others. Consequently, herbal remedies that produced synergistic effects with conventional antimalarial drugs may be prospects for standardization and development of antimalarial-medicinal plant combination therapy that could curtail malaria resistance to conventional antimalarial therapies.


2014 ◽  
Vol 81 (3) ◽  
pp. 1038-1046 ◽  
Author(s):  
Irene N. Kasumba ◽  
Aaron Bestor ◽  
Kit Tilly ◽  
Patricia A. Rosa

ABSTRACTTargeted mutagenesis and complementation are important tools for studying genes of unknown function in the Lyme disease spirocheteBorrelia burgdorferi. A standard method of complementation is reintroduction of a wild-type copy of the targeted gene on a shuttle vector. However, shuttle vectors are present at higher copy numbers thanB. burgdorferiplasmids and are potentially unstable in the absence of selection, thereby complicating analyses in the mouse-tick infectious cycle.B. burgdorferihas over 20 plasmids, with some, such as linear plasmid 25 (lp25), carrying genes required by the spirochetein vivobut relatively unstable duringin vitrocultivation. We propose that complementation on an endogenous plasmid such as lp25 would overcome the copy number andin vivostability issues of shuttle vectors. In addition, insertion of a selectable marker on lp25 could ensure its stable maintenance by spirochetes in culture. Here, we describe the construction of a multipurpose allelic-exchange vector containing a multiple-cloning site and either of two selectable markers. This suicide vector directs insertion of the complementing gene into thebbe02locus, a site on lp25 that was previously shown to be nonessential during bothin vitroandin vivogrowth. We demonstrate the functional utility of this strategy by restoring infectivity to anospCmutant through complementation at this site on lp25 and stable maintenance of theospCgene throughout mouse infection. We conclude that this represents a convenient and widely applicable method for stable gene complementation inB. burgdorferi.


2005 ◽  
Vol 11 (8) ◽  
pp. 1272-1282 ◽  
Author(s):  
Leif Abrell ◽  
Pablo G. Guerenstein ◽  
Wendy L. Mechaber ◽  
Gert Stange ◽  
Thomas A. Christensen ◽  
...  

2001 ◽  
Vol 204 (21) ◽  
pp. 3693-3702 ◽  
Author(s):  
Mark A. Frye

SUMMARYTo characterize the in vivo responses of the wing hinge stretch receptor of Manduca sexta, I recorded its activity and simultaneously tracked the up-and-down motion of the wing while the hawkmoth flew tethered in a wind tunnel. The stretch receptor fires a high-frequency burst of spikes near each dorsal stroke reversal. The onset of the burst is tightly tuned to a set-point in wing elevation, and the number of spikes contained within the burst encodes the maximal degree of wing elevation during the stroke. In an effort to characterize its mechanical encoding properties, I constructed an actuator that delivered deformations to the wing hinge and simultaneously recorded the resultant stretch and tension and the activity of the stretch receptor. Stimuli included stepwise changes in length as well as more natural dynamic deformation that was measured in vivo. Step changes in length reveal that the stretch receptor encodes the static amplitude of stretch with both phasic and tonic firing dynamics. In vivo sinusoidal deformation revealed (i) that the timing of stretch receptor activity is tightly phase-locked within the oscillation cycle, (ii) that the number of spikes per burst is inversely related to oscillation frequency and (iii) that the instantaneous frequency of the burst increases with oscillation rate. At all oscillation rates tested, the instantaneous frequency of the burst increases with amplitude.


1994 ◽  
Vol 189 (1) ◽  
pp. 55-67
Author(s):  
R Parthasarathy ◽  
W R Harvey

The time-dependent fluorescence intensity of an intravesicular potential-sensitive dye was used to probe the real-time kinetics of potential difference (PD)-dependent amino acid/Na+ symport at pH9 into brush-border membrane vesicles obtained from larval Manduca sexta midgut. Neutral amino acids (alanine, proline) are symported at higher rates as the vesicles are hyperpolarized. The symport rates of acidic (glutamate) and basic (arginine) amino acids are almost PD-independent. The half-saturation constant of alanine is PD-independent between -108 and -78 mV, although the maximal symport velocity increases by half as the voltage is increased. Amino acid throughput is evidently enhanced as the relatively high transmembrane PDs (> 150 mV, lumen positive) measured in vivo are approached. The half-saturation concentrations of Na+ were in the range 15-40 mmol l-1 for most of the amino acids examined and increased with voltage for alanine. The Vmax observed as a function of cation or amino acid concentration increased as the vesicle was hyperpolarized in the case of leucine and alanine. The data support the hypothesis that carrier and substrates are at equilibrium inasmuch as substrate translocation seems to be the rate-determining step of symport.


2012 ◽  
Vol 39 (1) ◽  
pp. 76-89 ◽  
Author(s):  
Carolina E. Reisenman ◽  
Jeffrey A. Riffell ◽  
Kristin Duffy ◽  
Adrien Pesque ◽  
David Mikles ◽  
...  

1992 ◽  
Vol 6 ◽  
pp. 174-174 ◽  
Author(s):  
Conrad C. Labandeira

A considerable amount of research has been devoted toward evaluating the impact of the Cretaceous/Tertiary extinction on terrestrial life. This research has focused primarily on terrestrial vertebrates (primarily dinosaurs), marine invertebrates (notably molluscs and foraminifera), and to a lesser extent, terrestrial vascular plants. Terrestrial arthropods, especially insects, have seldomly been investigated, principally because of an alleged depauperate fossil record. Nevertheless, within the past two decades, some of the most productive and taxonomically diverse insect faunas have originated from Cretaceous amber- and compression-fossil deposits from every continent. Whereas it was once thought that the Cretaceous represented an unknown void in the understanding of insect evolution, now it appears that many extant lineages are traceable to Cretaceous precursors.Three approaches are available for determining the extent of the effect of the terminal Cretaceous extinction event on insects. Assessed for the interval from the Early Cretaceous to the Early Paleogene, these approaches are: (1) establishing the secular pattern of familial- and generic-based taxonomic diversity (macroevolution); (2) recognizing the persistence or eradication of specific insect/vascular plant interactions, such as leaf-mining, wood-boring and pollination (behavior); and (3) establishing temporal trends in the range of mouthpart design, as an indicator of faunal disparity or structural diversity (morphology). These three operationally separate but complimentary approaches allow the advantage of using distinct data bases to bear on a common question. The body-fossil record of insects provides primary data for the taxonomic expansion, steady-state, or contraction of insect faunas. The trace-fossil record of those insect interactions that are coevolved with plant hosts reveals the temporal continuity of highly stereotyped and taxonomically obligate behaviors. Both of these are contrasted to an assessment of insectan structural disparity, herein determined from a robust data base of 30 modern insect mouthpart classes that are traced back in geologic time.A preliminary analysis of each of these three approaches indicates broad agreement–namely that insects were not dramatically affected by the terminal Cretaceous extinction event. First, insects experienced only a modest decline in diversity, about 9 percent at the family level. (The generic level is not yet analyzed.) Second, although the data base is limited, there is no indication of the extinction of major leaf-mining, wood-boring, pollinating or other plant-specific behaviors at the end of the Cretaceous. In fact, leaf-mine morphologies for three lepidopteran families with Cretaceous occurrences are apparently indistinguishable from their modern descendants. Last, of the 30 mouthpart classes occurring during the Paleogene, 28 are represented during the Cretaceous. These data provide strong evidence for a largely uninterrupted continuum of insect faunas across the Cretaceous/Tertiary boundary as measured by taxonomic diversity, coevolved behavior, and structural disparity.Because of abundant and often intimate associations between insects and flowering plants, these results are consistent with a gradual and not catastrophic change in terrestrial floras across the Cretaceous/Tertiary boundary. Acceptance of a catastrophic extinction of flowering plants during the terminal Cretaceous would necessitate an unprecedented level of host-switching by coevolved insects on contemporaneous plants. This is unlikely, based on evidence from the prolific literature on modern insect/plant interactions. These studies indicate the ubiquity of obligate insect specificity for various secondary chemicals on many flowering plant species.


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