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1.
Brain Commun ; 6(2): fcae082, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38572270

RESUMO

The posterior cingulate cortex (PCC) is a key hub of the default mode network underlying autobiographical memory retrieval, which falters early in the progression of Alzheimer's disease (AD). We recently performed RNA sequencing of post-mortem PCC tissue samples from 26 elderly Rush Religious Orders Study participants who came to autopsy with an ante-mortem diagnosis of no cognitive impairment but who collectively displayed a range of Braak I-IV neurofibrillary tangle stages. Notably, cognitively unimpaired subjects displaying high Braak stages may represent cognitive resilience to AD pathology. Transcriptomic data revealed elevated synaptic and ATP-related gene expression in Braak Stages III/IV compared with Stages I/II, suggesting these pathways may be related to PCC resilience. We also mined expression profiles for small non-coding micro-RNAs (miRNAs), which regulate mRNA stability and may represent an underexplored potential mechanism of resilience through the fine-tuning of gene expression within complex cellular networks. Twelve miRNAs were identified as differentially expressed between Braak Stages I/II and III/IV. However, the extent to which the levels of all identified miRNAs were associated with subject demographics, neuropsychological test performance and/or neuropathological diagnostic criteria within this cohort was not explored. Here, we report that a total of 667 miRNAs are significantly associated (rho > 0.38, P < 0.05) with subject variables. There were significant positive correlations between miRNA expression levels and age, perceptual orientation and perceptual speed. By contrast, higher miRNA levels correlated negatively with semantic and episodic memory. Higher expression of 15 miRNAs associated with lower Braak Stages I-II and 47 miRNAs were associated with higher Braak Stages III-IV, suggesting additional mechanistic influences of PCC miRNA expression with resilience. Pathway analysis showed enrichment for miRNAs operating in pathways related to lysine degradation and fatty acid synthesis and metabolism. Finally, we demonstrated that the 12 resilience-related miRNAs differentially expressed in Braak Stages I/II versus Braak Stages III/IV were predicted to regulate mRNAs related to amyloid processing, tau and inflammation. In summary, we demonstrate a dynamic state wherein differential PCC miRNA levels are associated with cognitive performance and post-mortem neuropathological AD diagnostic criteria in cognitively intact elders. We posit these relationships may inform miRNA transcriptional alterations within the PCC relevant to potential early protective (resilience) or pathogenic (pre-clinical or prodromal) responses to disease pathogenesis and thus may be therapeutic targets.

2.
J Agric Food Chem ; 72(5): 2467-2472, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38264806

RESUMO

Leptoglossus (Hemiptera: Coreidae) are a diverse genus of phytophagous insects. Literature regarding Leptoglossus has increased as species are identified as emerging agricultural pests or reported outside of their native range. Within Leptoglossus, five species dominate the literature and are known pests and vectors of plant pathogenic microbes in several major crops. Despite the increasing profile of Leptoglossus, current monitoring and management methods rely primarily on visual inspection, and semiochemical tools have yet to be developed. This Perspective identifies and discusses gaps in the Leptoglossus literature as well as areas of research needed for the development of effective tools for monitoring insect populations and enabling informed pest-management practices.


Assuntos
Heterópteros , Insetos , Animais , Agricultura , Controle de Pragas , Produtos Agrícolas
3.
NPJ Parkinsons Dis ; 10(1): 7, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38172128

RESUMO

Examination of early phases of synucleinopathy when inclusions are present, but long before neurodegeneration occurs, is critical to both understanding disease progression and the development of disease modifying therapies. The rat alpha-synuclein (α-syn) preformed fibril (PFF) model induces synchronized synucleinopathy that recapitulates the pathological features of Parkinson's disease (PD) and can be used to study synucleinopathy progression. In this model, phosphorylated α-syn (pSyn) inclusion-containing neurons and reactive microglia (major histocompatibility complex-II immunoreactive) peak in the substantia nigra pars compacta (SNpc) months before appreciable neurodegeneration. However, it remains unclear which specific genes are driving these phenotypic changes. To identify transcriptional changes associated with early synucleinopathy, we used laser capture microdissection of the SNpc paired with RNA sequencing (RNASeq). Precision collection of the SNpc allowed for the assessment of differential transcript expression in the nigral dopamine neurons and proximal glia. Transcripts upregulated in early synucleinopathy were mainly associated with an immune response, whereas transcripts downregulated were associated with neurotransmission and the dopamine pathway. A subset of 29 transcripts associated with neurotransmission/vesicular release and the dopamine pathway were verified in a separate cohort of males and females to confirm reproducibility. Within this subset, fluorescent in situ hybridization (FISH) was used to localize decreases in the Syt1 and Slc6a3 transcripts to pSyn inclusion-containing neurons. Identification of transcriptional changes in early synucleinopathy provides insight into the molecular mechanisms driving neurodegeneration.

4.
Phytochemistry ; 218: 113957, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38154731

RESUMO

Plant-derived volatiles are important mediators of plant-insect interactions as they can provide cues for host location and quality, or act as direct or indirect defense molecules. The volatiles produced by Zea mays (maize) include a range of terpenes, likely produced by several of the terpene synthases (TPS) present in maize. Determining the roles of specific terpene volatiles and individual TPSs in maize-insect interactions is challenging due to the promiscuous nature of TPSs in vitro and their potential for functional redundancy. In this study, we used metabolite GWAS of a sweetcorn diversity panel infested with Spodoptera frugiperda (fall armyworm) to identify genetic correlations between TPSs and individual volatiles. This analysis revealed a correlation between maize terpene synthase 1 (ZmTPS1) and emission of the monoterpene volatiles linalool and ß-myrcene. Electroantennogram assays showed gravid S. frugiperda could detect both linalool and ß-myrcene. Quantification of headspace volatiles in a maize tps1 loss-of-function mutant confirmed that ZmTPS1 is an important contributor to linalool and ß-myrcene emission in maize. Furthermore, pairwise choice assays between tps1 mutant and wild-type plants showed that ZmTPS1, and by extension its volatile products, aid host location in the chewing insect S. frugiperda, yet repel the sap-sucking pest, Rhopalosiphum maidis (corn leaf aphid). On the other hand, ZmTPS1 had no impact on indirect defense via the recruitment of the parasitoid Cotesia marginiventris. ZmTPS1 is therefore an important mediator of the interactions between maize and its insect pests.


Assuntos
Monoterpenos Acíclicos , Alquil e Aril Transferases , Terpenos , Zea mays , Animais , Terpenos/metabolismo , Zea mays/genética , Zea mays/metabolismo , Monoterpenos/metabolismo , Insetos , Spodoptera
5.
Pest Manag Sci ; 79(12): 4906-4920, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37545181

RESUMO

BACKGROUND: Spotted-wing drosophila, Drosophila suzukii, is a serious pest of thin-skinned fruits. Alternative methods to control this pest are needed to reduce insecticide use, including new repellents. Previous research demonstrated that D. suzukii adults use odor cues to avoid blueberries infected with the fungal pathogen Colletotrichum fioriniae, which causes the disease anthracnose. To identify novel D. suzukii repellents, we investigated the volatile emission from experimentally-infected fruit, which were inoculated with C. fioriniae isolates in the laboratory, and from field-collected fruit, which were naturally infected and harvested from a field. We then tested the pathogen-induced volatiles on D. suzukii adult behavior. RESULTS: Volatile emission was similar between all five C. fioriniae strains, with good agreement between experimentally-infected and field-collected berries. In total, 14 volatiles were found to be more abundant in infected versus uninfected fruit headspace. In multiple-choice bioassays, nine of the 14 volatiles elicited repellency responses from adult D. suzukii. These nine volatiles were further evaluated in dual choice assays, where all nine reduced fly capture by 43-96% compared to the control. The most repellent compounds tested were the esters ethyl butanoate and ethyl (E)-but-2-enoate, which were more or equally repellent to the known D. suzukii repellents 1-octen-3-ol, geosmin, and 2-pentylfuran. Dose-response assays identified concentration-dependent effects on D. suzukii repellency and oviposition when applied individually and consistent aversion observed across doses of a 1:1 blend. CONCLUSION: We report two repellents from C. fioriniae-infected blueberries that could be useful semiochemicals for the behavioral manipulation of D. suzukii in the field. © 2023 Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.


Assuntos
Mirtilos Azuis (Planta) , Repelentes de Insetos , Animais , Feminino , Humanos , Odorantes , Drosophila/fisiologia , Oviposição , Frutas/química , Repelentes de Insetos/farmacologia , Controle de Insetos/métodos
6.
Hand (N Y) ; 18(1_suppl): 56S-61S, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-34933606

RESUMO

BACKGROUND: Our purpose was to describe structural and morphological features of the median nerve and carpal tunnel on magnetic resonance imaging (MRI) studies obtained before, immediately after, 6 weeks after, and 6 years after endoscopic carpal tunnel release (ECTR). METHODS: In this prospective cohort study, 9 patients with a diagnosis of carpal tunnel syndrome (CTS) underwent ECTR. Standardized MRI studies were obtained before ECTR, immediately after ECTR, and 6 weeks and 6 years after surgery. Structural and morphological features of the median nerve and carpal tunnel were measured and assessed for each study with comparisons made between each time point. RESULTS: All 9 patients had complete symptom resolution postoperatively. On the immediate postoperative MRI, there was a discrete gap in the transverse carpal ligament in all patients. There was retinacular regrowth noted at 6 weeks in all cases. The median nerve cross-sectional area and the anterior-posterior dimension of the carpal tunnel at the level of the hamate increased immediately after surgery and these changes were maintained at 6 years. CONCLUSIONS: We defined structural and morphological changes on MRI for the median nerve and carpal tunnel in patients with continued symptom resolution 6 years after ECTR. Changes in median nerve and carpal tunnel morphology that occur immediately after surgery remain unchanged at mid-term follow-up in asymptomatic patients. Established imaging criteria for CTS may not apply to postoperative patients. Magnetic resonance imaging appears to be of limited clinical utility in the workup of persistent or recurrent CTS.


Assuntos
Síndrome do Túnel Carpal , Nervo Mediano , Humanos , Nervo Mediano/diagnóstico por imagem , Nervo Mediano/cirurgia , Síndrome do Túnel Carpal/diagnóstico por imagem , Síndrome do Túnel Carpal/cirurgia , Seguimentos , Estudos Prospectivos , Ligamentos
7.
Pest Manag Sci ; 79(4): 1585-1592, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36533692

RESUMO

BACKGROUND: Tephritid fruit flies are a major constraint to the global production of horticultural crops. In Africa, an array of native and alien invasive fruit fly species represents a key challenge to the horticultural industry. In an effort to develop a safer management tool for these pests, we previously identified glutathione (GSH) and glutamic acid (GA), as the host marking pheromones (HMPs) of Ceratitis cosyra and Ceratitis rosa, respectively. Here, we report on the effectiveness of these compounds (GSH and GA) in reducing natural fruit fly population infestations in mango orchards. Mango trees at two different agroecological zones in Kenya were sprayed with HMPs, and the fruits sampled periodically and assessed for fruit fly emergence. Fruit fly emergence data were compared to two controls, the positive control using spot spraying of food bait (SS), and the negative control using water (W). RESULTS: The two HMPs and SS substantially decreased fruit fly emergence from the sampled mangoes. GSH and GA treated mangoes showed reduced C. cosyra and C. rosa infestation by ~70-75% relative to control (W), and with variation noted in the pheromone applied and the recovered fruit fly species. The adult emergence in pheromone-treated plants compared favorably with the positive control SS. However, the HMPs had little impact on reducing Bactrocera dorsalis infestation of mangoes. CONCLUSION: The decrease in fruit fly emergence in sampled mango fruits from HMP treated trees corroborate previous laboratory results and support the prospect of using HMPs in the management of African fruit fly species. © 2022 Society of Chemical Industry.


Assuntos
Mangifera , Tephritidae , Animais , Ácido Glutâmico , Quênia , Feromônios , Drosophila , Glutationa
8.
Phytochemistry ; 206: 113519, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36462541

RESUMO

Infestation of agricultural commodities by insect pests results in significant economic, import and export, food safety, and invasive insect introduction issues for growers, consumers, and inspectors. The Oriental fruit fly (Bactrocera dorsalis) is considered a highly invasive insect pest with populations reported in more than 60 countries, with prevalent distributions in Asia and Africa. B. dorsalis is phytophagous with a host range encompassing hundreds of fruits and vegetables. Damage to the fruit or vegetable is inflicted through oviposition and subsequent larval feeding resulting in spoilage. Early detection of insect pest infestations is a critical component for ensuring food safety as well as controlling introduction and spread of invasive insects. However, detection of ovipositional activity and early larval development is visually difficult, thus rapid and non-destructive detection often relies on odors associated with infestation. We investigated the odors of mangoes (Mangifera indica L.) infested with B. dorsalis and compared the volatile profiles of infested mangoes to non-infested and mechanically damaged mangoes 24 h post-infestation. GC-MS and multivariate analyses provided the identification of eleven compounds unique to infested mangoes compared to mechanically damaged or non-infested fruit. Results indicated compositional and quantitative differentiation of volatile profiles among treatments for detection of infested fruit at quality checks or points of commerce.


Assuntos
Mangifera , Tephritidae , Animais , Feminino , Oviposição , Frutas , Cromatografia Gasosa-Espectrometria de Massas
9.
mBio ; 13(6): e0309622, 2022 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-36445080

RESUMO

During vertebrate infection, obligate intracellular malaria parasites develop within a parasitophorous vacuole, which constitutes the interface between the parasite and its hepatocyte or erythrocyte host cells. To traverse this barrier, Plasmodium spp. utilize a dual-function pore formed by EXP2 for nutrient transport and, in the context of the PTEX translocon, effector protein export across the vacuole membrane. While critical to blood-stage survival, less is known about EXP2/PTEX function in the liver stage, although major differences in the export mechanism are suggested by absence of the PTEX unfoldase HSP101 in the intrahepatic vacuole. Here, we employed the glucosamine-activated glmS ribozyme to study the role of EXP2 during Plasmodium berghei liver-stage development in hepatoma cells. Insertion of the glmS sequence into the exp2 3' untranslated region (UTR) enabled glucosamine-dependent depletion of EXP2 after hepatocyte invasion, allowing separation of EXP2 function during intrahepatic development from a recently reported role in hepatocyte invasion. Postinvasion EXP2 knockdown reduced parasite size and largely abolished expression of the mid- to late-liver-stage marker LISP2. As an orthogonal approach to monitor development, EXP2-glmS parasites and controls were engineered to express nanoluciferase. Activation of glmS after invasion substantially decreased luminescence in hepatoma monolayers and in culture supernatants at later time points corresponding to merosome detachment, which marks the culmination of liver-stage development. Collectively, our findings extend the utility of the glmS ribozyme to study protein function in the liver stage and reveal that EXP2 is important for intrahepatic parasite development, indicating that PTEX components also function at the hepatocyte-parasite interface. IMPORTANCE After the mosquito bite that initiates a Plasmodium infection, parasites first travel to the liver and develop in hepatocytes. This liver stage is asymptomatic but necessary for the parasite to transition to the merozoite form, which infects red blood cells and causes malaria. To take over their host cells, avoid immune defenses, and fuel their growth, these obligately intracellular parasites must import nutrients and export effector proteins across a vacuole membrane in which they reside. In the blood stage, these processes depend on a translocon called PTEX, but it is unclear if PTEX also functions during the liver stage. Here, we adapted the glmS ribozyme to control expression of EXP2, the membrane pore component of PTEX, during the liver stage of the rodent malaria parasite Plasmodium berghei. Our results show that EXP2 is important for intracellular development in the hepatocyte, revealing that PTEX components are also functionally important during liver-stage infection.


Assuntos
Eritrócitos , Hepatócitos , Malária , Plasmodium berghei , Proteínas de Protozoários , Carcinoma Hepatocelular , Eritrócitos/metabolismo , Eritrócitos/parasitologia , Neoplasias Hepáticas , Malária/genética , Malária/metabolismo , Malária/parasitologia , Plasmodium berghei/genética , Plasmodium berghei/metabolismo , Plasmodium falciparum/genética , Transporte Proteico/genética , Transporte Proteico/fisiologia , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , RNA Catalítico/metabolismo , Animais , Camundongos , Hepatócitos/metabolismo , Hepatócitos/parasitologia
10.
Eur J Med Chem ; 243: 114751, 2022 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-36191407

RESUMO

Malaria is caused by the parasite Plasmodium falciparum, which contains an essential non-photosynthetic plastid called the apicoplast. A single DNA polymerase, apPOL, is targeted to the apicoplast, where it replicates and repairs the genome. apPOL has no direct orthologs in mammals and is considered a promising drug target for the treatment and/or prevention of malaria. We previously reported screening the Malaria Box to identify MMV666123 as an inhibitor of apPOL. Herein we extend our studies and report structure-activity relationships for MMV666123 and identify key structural motifs necessary for inhibition. Although attempts to crystallize apPOL with the inhibitor were not fruitful, kinetic analysis and crystal structure determinations of WT and mutant apo-enzymes, facilitated model building and provided insights into the putative inhibitor binding site. Our results validate apPOL as an antimalarial target and provide an avenue for the design of high potency, specific inhibitors of apPOL and other A-family DNA polymerases.


Assuntos
Antimaláricos , Apicoplastos , Malária , Animais , Apicoplastos/genética , Apicoplastos/metabolismo , Plasmodium falciparum , Antimaláricos/metabolismo , Cinética , DNA Polimerase Dirigida por DNA , Malária/tratamento farmacológico , Proteínas de Protozoários/metabolismo , Mamíferos/metabolismo
11.
J Vis Exp ; (184)2022 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-35815999

RESUMO

Identification and isolation of contagious individuals along with quarantine of close contacts, is critical for slowing the spread of COVID-19. Large-scale testing in a surveillance or screening capacity for asymptomatic carriers of COVID-19 provides both data on viral spread and the follow-up ability to rapidly test individuals during suspected outbreaks. The COVID-19 early detection program at Michigan State University has been utilizing large-scale testing in a surveillance or screening capacity since fall of 2020. The methods adapted here take advantage of the reliability, large sample volume, and self-collection benefits of saliva, paired with a cost-effective, reagent conserving two-dimensional pooling scheme. The process was designed to be adaptable to supply shortages, with many components of the kits and the assay easily substituted. The processes outlined for collecting and processing SARS-CoV-2 samples can be adapted to test for future viral pathogens reliably expressed in saliva. By providing this blueprint for universities or other organizations, preparedness plans for future viral outbreaks can be developed.


Assuntos
COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , Teste para COVID-19 , Humanos , Reprodutibilidade dos Testes , Saliva , Manejo de Espécimes
12.
J Agric Food Chem ; 70(22): 6658-6669, 2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35613461

RESUMO

Plant parasitic nematodes (PPNs) develop through three major stages in their life cycle: hatching, infection, and reproduction. Interruption of any of these stages can affect their growth and survival. We used screenhouse pot experiments, laboratory in vitro hatching and mortality assays, and chemical analysis to test the hypothesis that the non-host Asteraceae plant vegetable black-jack (Bidens pilosa) suppresses infection of the PPN Meloidogyne incognita in two susceptible Solanaceae host plants, tomato (Solanum lycopersicum) and black nightshade (S. nigrum). In intercrop and drip pot experiments, B. pilosa significantly reduced the number of galls and egg masses in root-knot nematode (RKN)-susceptible host plants by 3-9-fold compared to controls. Chemical analysis of the most bioactive fraction from the root exudates of B. pilosa identified several classes of compounds, including vitamins, a dicarboxylic acid, amino acids, aromatic acids, and a flavonoid. In in vitro assays, the vitamins and aromatic acids elicited the highest inhibition in egg hatching, whereas ascorbic acid (vitamin) and 2-hydroxybenzoic acid (aromatic acid) elicited strong nematicidal activity against M. incognita, with LC50/48 h values of 12 and 300 ng/µL, respectively. Our results provide insights into how certain non-host plants can be used as companion crops to disrupt PPN infestation.


Assuntos
Solanum lycopersicum , Tylenchoidea , Animais , Produtos Agrícolas , Solanum lycopersicum/parasitologia , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Raízes de Plantas/parasitologia , Verduras , Vitaminas
13.
Cereb Cortex ; 32(22): 5108-5120, 2022 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-35076713

RESUMO

Mechanisms of Alzheimer's disease (AD) and its putative prodromal stage, amnestic mild cognitive impairment (aMCI), involve the dysregulation of multiple candidate molecular pathways that drive selective cellular vulnerability in cognitive brain regions. However, the spatiotemporal overlap of markers for pathway dysregulation in different brain regions and cell types presents a challenge for pinpointing causal versus epiphenomenal changes characterizing disease progression. To approach this problem, we performed Weighted Gene Co-expression Network Analysis and STRING interactome analysis of gene expression patterns quantified in frontal cortex samples (Brodmann area 10) from subjects who died with a clinical diagnosis of no cognitive impairment, aMCI, or mild/moderate AD. Frontal cortex was chosen due to the relatively protracted involvement of this region in AD, which might reveal pathways associated with disease onset. A co-expressed network correlating with clinical diagnosis was functionally associated with insulin signaling, with insulin (INS) being the most highly connected gene within the network. Co-expressed networks correlating with neuropathological diagnostic criteria (e.g., NIA-Reagan Likelihood of AD) were associated with platelet-endothelium-leucocyte cell adhesion pathways and hypoxia-oxidative stress. Dysregulation of these functional pathways may represent incipient alterations impacting disease progression and the clinical presentation of aMCI and AD.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Insulinas , Humanos , Doença de Alzheimer/patologia , Mapeamento Encefálico , Imageamento por Ressonância Magnética , Disfunção Cognitiva/patologia , Encéfalo , Lobo Frontal , Progressão da Doença
14.
J Agric Food Chem ; 69(50): 15145-15156, 2021 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-34882384

RESUMO

Olfactory cues guide plant parasitic nematodes (PPNs) to their host plants. We tested the hypothesis that non-host plant root volatiles repel PPNs. To achieve this, we compared the olfactory responses of infective juveniles (J2s) of the PPN Meloidogyne incognita to four non-host Asteraceae plants, namely, black-jack (Bidens pilosa), pyrethrum (Chrysanthemum cinerariifolium), marigold (Tagetes minuta), and sweet wormwood (Artemisia annua), traditionally used in sub-Saharan Africa for the management of PPNs. Chemical analysis by coupled gas chromatography-mass spectrometry (GC/MS) combined with random forest analysis, followed by behavioral assays, identified the repellents in the root volatiles of B. pilosa, T. minuta, and A. annua as (E)-ß-farnesene and 1,8-cineole, whereas camphor was attractive. In contrast, random forest analysis predicted repellents for C. cinerariifolium and A. annua as ß-patchoulene and isopropyl hexadecanoate. Our results suggested that terpenoids generally account for the repellency of non-host Asteraceae plants used in PPN management.


Assuntos
Asteraceae , Tylenchoidea , Animais , Cromatografia Gasosa-Espectrometria de Massas , Doenças das Plantas , Raízes de Plantas
15.
J Chem Ecol ; 47(12): 930-940, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34415499

RESUMO

Complex inter-organismal communication among plants, insects, and microbes in natural and agricultural ecological systems is typically governed by emitted and perceived semiochemicals. To understand and ultimately utilize the role of volatile semiochemicals in these interactions, headspace volatiles are routinely collected and analyzed. Numerous collection systems are available (e.g., static or dynamic; adsorption or absorption) where the choice of technique should be dependent upon the plant, insect, or microbial ecological system studied, the information sought, and the limitations of each method. Within these constraints, it remains necessary that each method detects and provides the accurate in situ, or in vitro, volatile profile of the studied system. Herein, we analyzed and compared the pros and cons of three solventless, thermal desorption systems (SPME, Tenax/cold trap, SPDE) using a synthetic standard blend of compounds mimicking a simple natural blend (benzaldehyde, b-caryophyllene, (Z)-3-hexenol, 6-methyl-5-hepten-2-one, and limonene). Direct splitless injection and Super Q collections of the standard blend were used as controls. The results indicated that related qualitative, as well as quantitative differences, could be correlated with adsorbent sampling capacity and structural bias. The results for Tenax/cold trap and SPDE also were affected by sampled headspace volumes. All solventless techniques exhibited high analytical reproducibility, with SPME and SPDE providing ease of use, low cost, and minimal instrument modifications. The more complex Tenax/cold trap technique provided higher collection efficiency. Using these results, we provide guidance for technique selection for chemical communication applications.


Assuntos
Extração em Fase Sólida/métodos , Manejo de Espécimes/métodos , Compostos Orgânicos Voláteis/análise , Reprodutibilidade dos Testes , Extração em Fase Sólida/instrumentação , Manejo de Espécimes/instrumentação
16.
J Chem Ecol ; 47(8-9): 799-809, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34347233

RESUMO

Fall armyworm (Spodoptera frugiperda) is a major global pest of many crops, including maize (Zea mays). This insect is known to use host plant-derived volatile organic compounds to locate suitable hosts during both its adult and larval stages, yet the function of individual compounds remains mostly enigmatic. In this study, we use a combination of volatile profiling, electrophysiological assays, pair-wise choice behavioral assays, and chemical supplementation treatments to identify and assess specific compounds from maize that influence S. frugiperda host location. Our findings reveal that methyl salicylate and (E)-alpha-bergamotene are oviposition attractants for adult moths but do not impact larval behavior. While geranyl acetate can act as an oviposition attractant or repellent depending on the host volatile context and (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) is an oviposition deterrent. These compounds can also be attractive to the larvae when applied to specific maize inbreds. These data show that S. frugiperda uses different plant volatile cues for host location in its adult and larval stage and that the background volatile context that specific volatiles are perceived in, alters their impact as behavioral cues.


Assuntos
Herbivoria/efeitos dos fármacos , Oviposição/efeitos dos fármacos , Spodoptera/fisiologia , Compostos Orgânicos Voláteis/farmacologia , Zea mays/química , Animais , Compostos Bicíclicos com Pontes/isolamento & purificação , Compostos Bicíclicos com Pontes/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Larva/fisiologia , Folhas de Planta/química , Folhas de Planta/metabolismo , Análise de Componente Principal , Salicilatos/isolamento & purificação , Salicilatos/farmacologia , Spodoptera/crescimento & desenvolvimento , Terpenos/isolamento & purificação , Terpenos/farmacologia , Compostos Orgânicos Voláteis/química , Zea mays/metabolismo
17.
Environ Microbiol ; 23(8): 4141-4150, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33876542

RESUMO

Floral nectar often contains pollen and microorganisms, which may change nectar's chemical composition, and in turn impact pollinator affinity. However, their individual and combined effects remain understudied. Here, we examined the impacts of the nectar specialist yeast, Metschnikowia reukaufii, and the addition of sunflower (Hellianthus annus) pollen. Pollen grains remained intact, yet still increased yeast growth and amino acid concentrations in nectar, whereas yeast depleted amino acids. Pollen, but not yeast, changed nectar sugar concentrations by converting sucrose to its monomers. Both pollen and yeast contributed emissions from nectar, though yeast volatiles were more abundant than pollen volatiles. Yeast volatile emission was positively correlated with pollen concentration and cell density, and yeast depleted a subset of pollen-derived volatiles. Honey bees avoided foraging on yeast-inoculated nectar and foraged equally among uninoculated nectars regardless of pollen content, underscoring the importance of microbial metabolites in mediating pollinator foraging.


Assuntos
Néctar de Plantas , Polinização , Animais , Abelhas , Odorantes , Pólen , Leveduras
18.
Mol Psychiatry ; 26(10): 5636-5657, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-31942037

RESUMO

Alzheimer's disease (AD) is the most common age-related form of dementia, associated with deposition of intracellular neuronal tangles consisting primarily of hyperphosphorylated microtubule-associated protein tau (p-tau) and extracellular plaques primarily comprising amyloid- ß (Aß) peptide. The p-tau tangle unit is a posttranslational modification of normal tau protein. Aß is a neurotoxic peptide excised from the amyloid-ß precursor protein (APP) by ß-site APP-cleaving enzyme 1 (BACE1) and the γ-secretase complex. MicroRNAs (miRNAs) are short, single-stranded RNAs that modulate protein expression as part of the RNA-induced silencing complex (RISC). We identified miR-298 as a repressor of APP, BACE1, and the two primary forms of Aß (Aß40 and Aß42) in a primary human cell culture model. Further, we discovered a novel effect of miR-298 on posttranslational levels of two specific tau moieties. Notably, miR-298 significantly reduced levels of ~55 and 50 kDa forms of the tau protein without significant alterations of total tau or other forms. In vivo overexpression of human miR-298 resulted in nonsignificant reduction of APP, BACE1, and tau in mice. Moreover, we identified two miR-298 SNPs associated with higher cerebrospinal fluid (CSF) p-tau and lower CSF Aß42 levels in a cohort of human AD patients. Finally, levels of miR-298 varied in postmortem human temporal lobe between AD patients and age-matched non-AD controls. Our results suggest that miR-298 may be a suitable target for AD therapy.


Assuntos
Doença de Alzheimer , MicroRNAs , Doença de Alzheimer/genética , Secretases da Proteína Precursora do Amiloide/genética , Peptídeos beta-Amiloides , Precursor de Proteína beta-Amiloide/genética , Animais , Ácido Aspártico Endopeptidases/genética , Humanos , Camundongos , MicroRNAs/genética , Proteínas tau/genética
19.
Curr Opin Insect Sci ; 44: 23-34, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33096275

RESUMO

Many plant-associated microbial communities produce volatile signals that influence insect responses, yet the impact of floral microorganisms has received less attention than other plant microbiomes. Floral microorganisms alter plant and floral odors by adding their own emissions or modifying plant volatiles. These contextual and microbe species-specific changes in floral signaling are detectable by insects and can modify their behavior. Opportunities for future work in floral systems include identifying specific microbial semiochemicals that underlie insect behavioral responses and examining if insect species vary in their responses to microbial volatiles. Examining if documented patterns are consistent across diverse plant-microbe-insect interactions and in realistic plant-based studies will improve our understanding of how microbes mediate pollination interactions in complex system.


Assuntos
Flores/microbiologia , Insetos/fisiologia , Percepção Olfatória , Compostos Orgânicos Voláteis , Animais , Comportamento Animal , Feromônios
20.
Int J Exerc Sci ; 13(5): 912-923, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32922643

RESUMO

In order to excel in the National Football League (NFL) it would seem reasonable to assume an athlete has grit which consists of the constructs of consistency of interest and perseverance of effort. Grit-like qualities such as endurance, urgency and intensity, self-confidence, need for encouragement, and self-criticality may be of particular value for the athlete playing the Quarterback (QB) position. The purpose of the study was to assess the 5 grit-like constructs of endurance, urgency and intensity, self-confidence, need for encouragement, and self-criticality among NFL QBs. The Flippen ProfileTM assessment was administered to 29 NFL QBs and the 5 grit-like constructs were recorded. Each of the 5 grit-like constructs were scored on a scale of 0-100, where high scores were considered desirable for endurance, urgency and intensity, and self-confidence, while lower scores were considered as desirable for need for encouragement, and self-criticality. The scores for each of the 5 grit-like constructs were then partitioned by three categories of QB years played: 1-2 (n=8), 3-7 (n=13), and ≥8 (n=8) years. Four key findings emerged following the analysis: the NFL QBs scored favorably on all of the 5 grit-like constructs independent of years played, QBs with ≥8 years' experience scored the most favorably for endurance and the need for encouragement, QBs with 1-2 years' experience scored the most favorably for self-criticality. These results may provide coaches and athletes aspiring to play QB in the NFL with benchmarks regarding the 5 grit-like constructs that are associated with successful NFL QBs.

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