Aphid and caterpillar feeding drive similar patterns of induced defences and resistance to subsequent herbivory in wild cotton.

MAIN CONCLUSION: Our results indicate caterpillars and aphids cause similar levels of induced defences and resistance against caterpillars in wild cotton plants. These symmetrical effects are not consistent with patterns predicted by plant defensive signaling crosstalk and call for further work addressing the biochemical mechanisms underpinning these results. Plant-induced responses to attack often mediate interactions between different species of insect herbivores. These effects are predicted to be contingent on the herbivore's feeding guild, whereby prior feeding by insects should negatively impact subsequent feeding by insects of the same guild (induced resistance) but may positively influence insects of a different guild (induced susceptibility) due to interfering crosstalk between plant biochemical pathways specific to each feeding guild. We compared the effects of prior feeding by leaf-chewing caterpillars (Spodoptera frugiperda) vs. sap-sucking aphids (Aphis gossypii) on induced defences in wild cotton (Gossypium hirsutum) and the consequences of these attacks on subsequently feeding caterpillars (S. frugiperda). To this end, we conducted a greenhouse experiment where cotton plants were either left undamaged or first exposed to caterpillar or aphid feeding, and we subsequently placed caterpillars on the plants to assess their performance. We also collected leaves to assess the induction of chemical defences in response to herbivory. We found that prior feeding by both aphids and caterpillars resulted in reductions in consumed leaf area, caterpillar mass gain, and caterpillar survival compared with control plants. Concomitantly, prior aphid and caterpillar herbivory caused similar increases in phenolic compounds (flavonoids and hydroxycinnamic acids) and defensive terpenoids (hemigossypolone) compared with control plants. Overall, these findings indicate that these insects confer a similar mode and level of induced resistance in wild cotton plants, calling for further work addressing the biochemical mechanisms underpinning these effects.

Experimental Growth Conditions affect Direct and Indirect Defences in two Cotton Species.

Cotton has been used as a model plant to study direct and indirect plant defence against herbivorous insects. However, the plant growing conditions could have an important effect on the outcome of such plant defence studies. We examined how common experimental growth conditions influence constitutive and inducible defences in two species of cotton, Gossypium hirsutum and G. herbaceum. We induced plants by applying caterpillar regurgitant to mechanical wounds to compare the induction levels between plants of both species grown in greenhouse or phytotron conditions. For this we measured defence metabolites (gossypol and heliocides) and performance of Spodoptera frugiperda caterpillars on different leaves, the emission of plant volatiles, and their attractiveness to parasitic wasps. Induction increased the levels of defence metabolites, which in turn decreased the performance of S. frugiperda larvae. Constitutive and induced defence levels were the highest in plants grown in the phytotron (compared to greenhouse plants), G. hirsutum and young leaves. Defence induction was more pronounced in plants grown in the phytotron and in young leaves. Also, the differences between growing conditions were more evident for metabolites in the youngest leaves, indicating an interaction with plant ontogeny. The composition of emitted volatiles was different between plants from the two growth conditions, with greenhouse-grown plants showing more variation than phytotron-grown plants. Also, G. hirsutum released higher amounts of volatiles and attracted more parasitic wasps than G. herbaceum. Overall, these results highlight the importance of experimental abiotic factors in plant defence induction and ontogeny of defences. We therefore suggest careful consideration in selecting the appropriate experimental growing conditions for studies on plant defences.

Terpene chemotypes in Gossypium hirsutum (wild cotton) from the Yucatan Peninsula, Mexico.

Cultivated plants of Gossypium hirsutum Cav. (cotton) consistently emit low levels of volatile organic compounds, primarily mono- and sesquiterpenoids, which are produced and stored in pigment glands. In this study, we provide a comprehensive evaluation of the terpene profiles of wild G. hirsutum plants sourced from sites located throughout natural distribution of this species, thus providing the first in-depth assessment of the scope of its intraspecific chemotypic diversity. Chemotypic variation can potentially influence resistance to herbivory and diseases, or interact with abiotic stress such as extreme temperatures. Under controlled environmental conditions, plants were grown from seeds of sixteen G. hirsutum populations collected along the coastline of the Yucatan Peninsula, which is its likely centre of origin. We found high levels of intraspecific diversity in the terpene profiles of the plants. Two distinct chemotypes were identified: one chemotype contained higher levels of the monoterpenes γ-terpinene, limonene, α-thujene, α-terpinene, terpinolene, and p-cymene, while the other chemotype was distinguished by higher levels of α- and ß-pinene. The distribution of chemotypes followed a geographic gradient from west to east, with an increasing frequency of the former chemotype. Concurrent analysis of maternal plants revealed that chemotypes in wild G. hirsutum are highly heritable.

Hospitalization as an opportunity to engage underserved individuals in shared decision-making for lung cancer screening: results from two randomized pilot trials.

PURPOSE: Medicare requires tobacco dependence counseling and shared decision-making (SDM) for lung cancer screening (LCS) reimbursement. We hypothesized that initiating SDM during inpatient tobacco treatment visits would increase LCS among patients with barriers to proactively seeking outpatient preventive care. METHODS: We collected baseline assessments and performed two pilot randomized trials at our safety-net hospital. Pilot 1 tested feasibility, acceptability, and preliminary efficacy of a nurse practitioner initiating SDM for LCS during hospitalization (Inpatient SDM). We collected qualitative data on barriers encountered during Pilot 1. Pilot 2 added a community health worker (CHW) to address barriers to LCS completion (Inpatient SDM + CHW-navigation). For both studies, preliminary efficacy was an intention-to-treat analysis of LCS completion at 3 months between intervention and comparator (furnishing of LCS decision aid only) groups. RESULTS: Baseline assessments showed that patients preferred in-person LCS discussions versus self-reviewing materials; overall 20% had difficulty understanding written information. In Pilot 1, 4% (2/52) in Inpatient SDM versus 2% (1/48, comparator) completed LCS (p = 0.6), despite 89% (89/100) desiring LCS. Primary care providers noted that competing priorities and patient factors (e.g., social barriers to keeping appointments) prevented the intervention from working as intended. In Pilot 2, 50% (5/10) in Inpatient SDM + CHW-navigation versus 9% (1/11, comparator) completed LCS (p < 0.05). Many patients were ineligible due to recent diagnostic chest CT (Pilot 1: 255/659; Pilot 2: 239/527). CONCLUSIONS: Inpatient SDM + CHW-navigation shows promise to improve LCS rates among underserved patients who smoke, but feasibility is limited by recent diagnostic chest CT among inpatients. Implementing CHW-navigation in other clinical settings may facilitate LCS for underserved patients. TRAIL REGISTRATION: ClinicalTrials.gov Identifier: NCT03276806 (8 September 2017); NCT03793894 (4 January 2019).

Under fire-simultaneous volatilome and transcriptome analysis unravels fine-scale responses of tansy chemotypes to dual herbivore attack.

BACKGROUND: Tansy plants (Tanacetum vulgare L.) are known for their high intraspecific chemical variation, especially of volatile organic compounds (VOC) from the terpenoid compound group. These VOCs are closely involved in plant-insect interactions and, when profiled, can be used to classify plants into groups known as chemotypes. Tansy chemotypes have been shown to influence plant-aphid interactions, however, to date no information is available on the response of different tansy chemotypes to simultaneous herbivory by more than one insect species. RESULTS: Using a multi-cuvette system, we investigated the responses of five tansy chemotypes to feeding by sucking and/or chewing herbivores (aphids and caterpillars; Metopeurum fuscoviride Stroyan and Spodoptera littoralis Boisduval). Herbivory by caterpillars following aphid infestation led to a plant chemotype-specific change in the patterns of terpenoids stored in trichome hairs and in VOC emissions. The transcriptomic analysis of a plant chemotype represents the first de novo assembly of a transcriptome in tansy and demonstrates priming effects of aphids on a subsequent herbivory. Overall, we show that the five chemotypes do not react in the same way to the two herbivores. As expected, we found that caterpillar feeding increased VOC emissions, however, a priori aphid infestation only led to a further increase in VOC emissions for some chemotypes. CONCLUSIONS: We were able to show that different chemotypes respond to the double herbivore attack in different ways, and that pre-treatment with aphids had a priming effect on plants when they were subsequently exposed to a chewing herbivore. If neighbouring chemotypes in a field population react differently to herbivory/dual herbivory, this could possibly have effects from the individual level to the group level. Individuals of some chemotypes may respond more efficiently to herbivory stress than others, and in a group environment these "louder" chemotypes may affect the local insect community, including the natural enemies of herbivores, and other neighbouring plants.

Effect of plant chemical variation and mutualistic ants on the local population genetic structure of an aphid herbivore.

Plants exhibit impressive genetic and chemical diversity, not just between species but also within species, and the importance of plant intraspecific variation for structuring ecological communities is well known. When there is variation at the local population level, this can create a spatially heterogeneous habitat for specialised herbivores potentially leading to non-random distribution of individuals across host plants. Plant variation can affect herbivores directly and indirectly via a third species, resulting in variable herbivore growth rates across different host plants. Herbivores also exhibit within-species variation, with some genotypes better adapted to some plant variants than others. We genotyped aphids collected across 2 years from a field site containing ~200 patchily distributed host plants that exhibit high chemical diversity. The distribution of aphid genotypes, their ant mutualists, and other predators was assessed across the plants. We present evidence that the local distribution of aphid (Metopeurum fuscoviride) genotypes across host-plant individuals is associated with variation in the plant volatiles (chemotypes) and non-volatile metabolites (metabotypes) of their host plant tansy (Tanacetum vulgare). Furthermore, these interactions in the field were influenced by plant-host preferences of aphid-mutualist ants. Our results emphasise that plant intraspecific variation can structure ecological communities not only at the species level but also at the genetic level within species and that this effect can be enhanced through indirect interactions with a third species.

Metabotype variation in a field population of tansy plants influences aphid host selection.

It is well known that plant volatiles influence herbivores in their selection of a host plant; however, less is known about how the nonvolatile metabolome affects herbivore host selection. Metabolic diversity between intraspecific plants can be characterized using non-targeted mass spectrometry that gives us a snapshot overview of all metabolic processes occurring within a plant at a particular time. Here, we show that non-targeted metabolomics can be used to reveal links between intraspecific chemical diversity and ecological processes in tansy (Tanacetum vulgare). First, we show that tansy plants can be categorized into five subgroups based up on their metabolic profiles, and that these "metabotypes" influenced natural aphid colonization in the field. Second, this grouping was not due to induced metabolomic changes within the plant due to aphid feeding but rather resulted from constitutive differences in chemical diversity between plants. These findings highlight the importance of intraspecific chemical diversity within one plant population and provide the first report of a non-targeted metabolomic field study in chemical ecology.

Chemotypic variation in terpenes emitted from storage pools influences early aphid colonisation on tansy.

Tansy plants (Tanacetum vulgare L.) exhibit high chemical variation, particularly in mono- and sesquiterpenes that are stored in specialised glands on the plant surface. In the present work we investigated the effects of terpene chemotypes on Metopeurum fuscoviride, an aphid species specialised on tansy, and their tending ants, at the field scale. Previous studies have chemotyped tansy by assessing dominant compounds; here we propose a method of chemotyping using all volatile compounds that are likely emitted from the storage glands. The analysis is based on two extraction methods: GC-MS analysis of leaf hexane extracts and SBSE analysis of headspace emissions. In an initial screening we identified the subset of compounds present in both chemical patterns, labelled as 'compounds likely emitted from storage'. In a large field survey we could show that the putative chemotypic emission pattern from storage pools significantly affected the early aphid colonisation of tansy. Moreover, the statistical analyses revealed that minor compounds exerted a stronger influence on aphid and tending-ant presence than dominant compounds. Overall we demonstrated that within the enormous chemotypic variation of terpenes in tansy plants, chemical signatures of volatile terpenes can be related to the occurrence of insects on individual plants in the field.

Association of hip pain with radiographic evidence of hip osteoarthritis: diagnostic test study.

STUDY QUESTION: Is there concordance between hip pain and radiographic hip osteoarthritis? METHODS: In this diagnostic test study, pelvic radiographs were assessed for hip osteoarthritis in two cohorts: the Framingham Osteoarthritis Study (community of Framingham, Massachusetts) and the Osteoarthritis Initiative (a multicenter longitudinal cohort study of osteoarthritis in the United States). Using visual representation of the hip joint, participants reported whether they had hip pain on most days and the location of the pain: anterior, groin, lateral, buttocks, or low back. In the Framingham study, participants with hip pain were also examined for hip pain with internal rotation. The authors analysed the agreement between radiographic hip osteoarthritis and hip pain, and for those with hip pain suggestive of hip osteoarthritis they calculated the sensitivity, specificity, positive predictive value, and negative predictive value of radiographs as the diagnostic test. STUDY ANSWER AND LIMITATIONS: In the Framingham study (n=946), only 15.6% of hips in patients with frequent hip pain showed radiographic evidence of hip osteoarthritis, and 20.7% of hips with radiographic hip osteoarthritis were frequently painful. The sensitivity of radiographic hip osteoarthritis for hip pain localised to the groin was 36.7%, specificity 90.5%, positive predictive value 6.0%, and negative predictive value 98.9%. Results did not differ much for hip pain at other locations or for painful internal rotation. In the Osteoarthritis Initiative study (n=4366), only 9.1% of hips in patients with frequent pain showed radiographic hip osteoarthritis, and 23.8% of hips with radiographic hip osteoarthritis were frequently painful. The sensitivity of definite radiographic hip osteoarthritis for hip pain localised to the groin was 16.5%, specificity 94.0%, positive predictive value 7.1%, and negative predictive value 97.6%. Results also did not differ much for hip pain at other locations. WHAT THIS STUDY ADDS: Hip pain was not present in many hips with radiographic osteoarthritis, and many hips with pain did not show radiographic hip osteoarthritis. Most older participants with a high suspicion for clinical hip osteoarthritis (groin or anterior pain and/or painful internal rotation) did not have radiographic hip osteoarthritis, suggesting that in many cases, hip osteoarthritis might be missed if diagnosticians relied solely on hip radiographs. FUNDING, COMPETING INTERESTS, DATA SHARING: See the full paper on thebmj.com for funding. The authors have no competing interests. Additional data are available from bevochan@bu.edu.

Prevalence of radiographic and symptomatic hip osteoarthritis in an urban United States community: the Framingham osteoarthritis study.

OBJECTIVE: The last prevalence survey encompassing urban populations was part of the First National Health and Nutrition Examination Survey, conducted in the 1970s. The aim of the present study was to perform a prevalence survey of hip osteoarthritis (OA) among individuals in the Framingham Study Community cohort. METHODS: Individuals ages 50 years and older living in Framingham, Massachusetts in 2002-2005 were recruited by random digit dialing, with selection made regardless of whether joint pain or arthritis were reported. Anteroposterior radiographs of the long limbs of the lower extremities, including the pelvis, were obtained with individuals placed in a standing position. The radiographs were read by two trained physicians for the presence of radiographic hip OA, with all possible cases of radiographic hip OA confirmed by an experienced musculoskeletal radiologist. Radiographic hip OA was defined as a Kellgren/Lawrence radiographic severity grade of ≥2. Using a homunculus in which the hip joint was depicted, participants were asked whether they had hip pain on most days. Those who responded "yes" were defined as having hip pain. Symptomatic hip OA was defined as radiographic OA with ipsilateral hip pain. We defined a person as having hip OA if at least one of the hip joints was affected. RESULTS: Of 978 subjects studied (mean age 63.5 years; 56% women), the age-standardized prevalence of radiographic hip OA was 19.6% (95% confidence interval [95% CI] 16.7-23.0%) and the age-standardized prevalence of symptomatic hip OA was 4.2% (95% CI 2.9-6.1%). Overall, men were observed to have a higher prevalence of radiographic hip OA (P < 0.0001) compared to women, but men did not have a higher prevalence of symptomatic hip OA compared to women (5.2% versus 3%; P = 0.08). CONCLUSION: Hip OA is a common condition in middle-aged and older individuals in urban and suburban areas of the US.

Reducing unnecessary inpatient laboratory testing in a teaching hospital.

After an inpatient phlebotomy-laboratory test request audit for 2 general inpatient wards identified 5 tests commonly ordered on a recurring basis, a multidisciplinary committee developed a proposal to minimize unnecessary phlebotomies and laboratory tests by reconfiguring the electronic order function to limit phlebotomy-laboratory test requests to occur singly or to recur within one 24-hour window. The proposal was implemented in June 2003. Comparison of fiscal year volume data from before (2002-2003) and after (2003-2004) implementation revealed 72,639 (12.0%) fewer inpatient tests, of which 41,765 (57.5%) were related directly to decreases in the 5 tests frequently ordered on a recurring basis. Because the electronic order function changes did not completely eliminate unnecessary testing, we concluded that the decrease in inpatient testing represented a minimum amount of unnecessary inpatient laboratory tests. We also observed 17,207 (21.4%) fewer inpatient phlebotomies, a decrease sustained in fiscal year 20042005. Labor savings allowed us to redirect phlebotomists to our understaffed outpatient phlebotomy service.

Induction of sporulation in Saccharomyces cerevisiae leads to the formation of N6-methyladenosine in mRNA: a potential mechanism for the activity of the IME4 gene.

N6-methyladenosine (m6A) is present at internal sites in mRNA isolated from all higher eukaryotes, but has not previously been detected in the mRNA of the yeast Saccharomyces cerevisiae. This nucleoside modification occurs only in a sequence- specific context that appears to be conserved across diverse species. The function of this modification is not fully established, but there is some indirect evidence that m6A may play a role in the efficiency of mRNA splicing, transport or translation. The S.cerevisiae gene IME4, which is important for induction of sporulation, is very similar to the human gene MT-A70, which has been shown to be a critical subunit of the human mRNA [N6-adenosine]-methyltransferase. This observation led to the hypothesis that yeast sporulation may be dependent upon methylation of yeast mRNA, mediated by Ime4p. In this study we show that induction of sporulation leads to the appearance of low levels of m6A in yeast mRNA and that this modification requires IME4. Moreover, single amino acid substitutions in the putative catalytic residues of Ime4p lead to severe sporulation defects in a strain whose sporulation ability is completely dependent on this protein. Collectively, these data suggest very strongly that the activation of sporulation by Ime4p is the result of its proposed methyltransferase activity and provide the most direct evidence to date of a physiologic role of m6A in a gene regulatory pathway.