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1.
Soc Sci Res ; 119: 102980, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38609301

RESUMO

Why do economically disadvantaged people often regard inequality as fair? The literature on deliberative justice suggests that people regard inequality as fair when it is proportional to inequality in effort or other inputs - i.e. when it is meritocratic. But in the real-world there is substantial uncertainty over the distribution of income and merit - so what compels disadvantaged people to legitimate their own disadvantage? This paper suggests it is a reaction to cognitive dissonance. When inequality is high, and when people lack control, their only way to reduce dissonance is to convince themselves the distribution is fair. I implement an online experiment to test this theory. Results do not support a cognitive dissonance mechanism behind meritocracy. But they do indicate that disadvantaged individuals are more likely to regard inequality as fair when they lack control. Analysis of qualitative data indicates that deprivation of control engenders a fatalistic response to inequality.


Assuntos
Dissonância Cognitiva , Confiabilidade dos Dados , Humanos , Renda , Justiça Social , Populações Vulneráveis
2.
Am J Primatol ; 84(8): e23397, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35700311

RESUMO

The role of plant secondary metabolites (PSMs) in shaping the feeding decisions, habitat suitability, and reproductive success of herbivorous mammals has been a major theme in ecology for decades. Although primatologists were among the first to test these ideas, studies of PSMs in the feeding ecology of non-human primates have lagged in recent years, leading to a recent call for primatologists to reconnect with phytochemists to advance our understanding of the primate nutrition. To further this case, we present a formal meta-analysis of diet choice in response to PSMs based on field studies on wild primates. Our analysis of 155 measurements of primate feeding response to PSMs is drawn from 53 studies across 43 primate species which focussed primarily on the effect of three classes of PSMs tannins, phenolics, and alkaloids. We found a small but significant effect of PSMs on the diet choice of wild primates, which was largely driven by the finding that colobine primates showed a moderate aversion to condensed tannins. Conversely, there was no evidence that PSMs had a significant deterrent effect on food choices of non-colobine primates when all were combined into a single group. Furthermore, within the colobine primates, no other PSMs influenced feeding choices and we found no evidence that foregut anatomy significantly affected food choice with respect to PSMs. We suggest that methodological improvements related to experimental approaches and the adoption of new techniques including metabolomics are needed to advance our understanding of primate diet choice.


Assuntos
Comportamento Alimentar , Preferências Alimentares , Animais , Dieta/veterinária , Comportamento Alimentar/fisiologia , Mamíferos , Plantas/metabolismo , Primatas
3.
Oecologia ; 196(3): 795-803, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34142232

RESUMO

The diets of individual animals within populations can differ, but few studies determine whether this is due to fundamental differences in preferences or capacities to eat specific foods, or to external influences such as dominance hierarchies or spatial variation in food availability. The distinction is important because different drivers of dietary specialisation are likely to have different impacts on the way in which animal populations respond to, for example, habitat modification. We used a captive feeding study to investigate the mechanisms driving individual dietary specialisation in a population of wild koalas (Phascolarctos cinereus) in which individuals predominantly ate either Eucalyptus viminalis or Eucalyptus obliqua foliage. All six koalas that primarily ate E. viminalis in the wild avoided eating E. obliqua for more than 1 month in captivity. In contrast, all seven koalas that primarily ate E. obliqua could be maintained exclusively on this species in captivity, although they ate less from individual trees with higher foliar concentrations of unsubstituted B-ring flavanones (UBFs). Our results show that fundamental differences between individual animals allow some to exploit food resources that are less suitable for others. This could reduce competition for food, increase habitat carrying capacity, and is also likely to buffer the population against extinction in the face of habitat modification. The occurrence of fundamental individual specialisation within animal populations could also affect the perceived conservation value of different habitats, translocation or reintroduction success, and population dynamics. It should therefore be further investigated in other mammalian herbivore species.


Assuntos
Eucalyptus , Phascolarctidae , Animais , Dieta , Ecossistema , Árvores
4.
Prospects (Paris) ; 51(1-3): 261-277, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33941990

RESUMO

This article seeks to use Dewey's interpretation of pragmatism and education as a model for how dominant notions of school exemplify a colonizing theory of nature. The article argues that Dewey sought to commodify nature as a tool for human progress. This aspect of Dewey's beliefs is further demonstrated in the kind of schooling that is being implemented through globalization. The article draws on Indigenous concepts of the nature and the Earth, for decolonizing science instruction in an elementary classroom.

5.
Proc Biol Sci ; 287(1922): 20192364, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32156194

RESUMO

Somatic mutations can have important effects on the life history, ecology, and evolution of plants, but the rate at which they accumulate is poorly understood and difficult to measure directly. Here, we develop a method to measure somatic mutations in individual plants and use it to estimate the somatic mutation rate in a large, long-lived, phenotypically mosaic Eucalyptus melliodora tree. Despite being 100 times larger than Arabidopsis, this tree has a per-generation mutation rate only ten times greater, which suggests that this species may have evolved mechanisms to reduce the mutation rate per unit of growth. This adds to a growing body of evidence that illuminates the correlated evolutionary shifts in mutation rate and life history in plants.


Assuntos
Arabidopsis/fisiologia , Taxa de Mutação , Filogenia , Fenômenos Fisiológicos Vegetais
6.
New Phytol ; 225(1): 488-498, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31412143

RESUMO

Although tannins have been an important focus of studies of plant-animal interactions, traditional tannin analyses cannot differentiate between the diversity of structures present in plants. This has limited our understanding of how different mixtures of these widespread secondary metabolites contribute to variation in biological activity. We used UPLC-MS/MS to determine the concentration and broad composition of tannins and polyphenols in 628 eucalypt (Eucalyptus, Corymbia and Angophora) samples, and related these to three in vitro functional measures believed to influence herbivore defence: protein precipitation capacity, oxidative activity at high pH and capacity to reduce in vitro nitrogen (N) digestibility. Protein precipitation capacity was most strongly correlated with concentrations of procyanidin subunits in proanthocyanidins (PAs), and late-eluting ellagitannins. Capacity to reduce in vitro N digestibility was affected most by the subunit composition and mean degree of polymerisation (mDP) of PAs. Finally, concentrations of ellagitannins and prodelphinidin subunits of PAs were the strongest determinants of oxidative activity. The results illustrate why measures of total tannins rarely correlate with animal feeding responses. However, they also confirm that the analytical techniques utilised here could allow researchers to understand how variation in tannins influence the ecology of individuals and populations of herbivores, and, ultimately, other ecosystem processes.


Assuntos
Herbivoria/fisiologia , Folhas de Planta/metabolismo , Taninos/metabolismo , Modelos Estatísticos , Nitrogênio/metabolismo , Oxirredução , Polifenóis/metabolismo
7.
J Surg Res ; 255: 124-129, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32543377

RESUMO

BACKGROUND: There is currently limited data assessing the long-term consequences of thoracic endovascular aortic repair (TEVAR) in otherwise healthy aortic segments remote from the site of endograft coverage. The aim of this study is to retrospectively evaluate aortic remodeling and long-term outcomes of blunt thoracic aortic injury (BTAI) patients treated with TEVAR. Our hypothesis is that significant changes to the aorta proximal to the graft-covered segment are suspected following TEVAR. METHODS: An institutional review board-approved retrospective review of patients who underwent TEVAR for BTAI at a level I trauma center from 2004 to 2018 was performed. Forty-six patients were identified and of these, 32 patients with high-resolution computed tomographic angiography imaging follow-up were included in the study. Computed tomographic angiography measurements of aortic dimensions and branch vessels proximal, distal, and adjacent to the stent grafted segment were recorded preprocedure and postprocedure and analyzed. Primary device-related outcomes such as birdbeaking, mural thrombus, stent migration, and persistent endoleak were assessed. Patient outcomes including mortality, graft-related morbidity, and need for secondary interventions were also analyzed. RESULTS: Mean follow-up of the selected patients in the study was 1.52 y (range, 0.06-8.0 y). Following TEVAR, the ascending aortic length increased significantly (mean 5.7 ± 4.6 mm, P < 0.001). The mean diameters of the ascending aorta (1.5 ± 1.5, P < 0.001 mm), the midaortic arch (1.3 ± 1.7 mm, P < 0.001), and proximal and the distal endograft landing zones (1.9 ± 2.1 mm and 2.2 ± 1.6 mm, respectively, P < 0.001) also increased significantly following TEVAR. Clinically relevant device-related outcomes occurred with the presence of endograft infolding and subsequent development of endograft mural thrombus (P < 0.001). The need for secondary intervention following TEVAR for BTAI was associated with endograft mural thrombus (P < 0.05). CONCLUSIONS: TEVAR for BTAI causes significant geometric changes in the aorta proximal to the stented grafted segment of the aorta. Direct consequences of the graft at the stented segment includes mural thrombus development within the endograft which was associated with the need for secondary intervention. Although clinical significance is yet to be determined, post-TEVAR changes in aortic architecture warrant continued aortic surveillance following BTAI.


Assuntos
Aorta Torácica/lesões , Implante de Prótese Vascular/efeitos adversos , Procedimentos Endovasculares/efeitos adversos , Remodelação Vascular , Lesões do Sistema Vascular/cirurgia , Ferimentos não Penetrantes/cirurgia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Aorta Torácica/diagnóstico por imagem , Aorta Torácica/patologia , Aorta Torácica/cirurgia , Prótese Vascular/efeitos adversos , Implante de Prótese Vascular/instrumentação , Colonografia Tomográfica Computadorizada , Procedimentos Endovasculares/instrumentação , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Estudos Retrospectivos , Stents/efeitos adversos , Rigidez Vascular , Lesões do Sistema Vascular/patologia , Ferimentos não Penetrantes/patologia , Adulto Jovem
8.
New Phytol ; 223(3): 1489-1504, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31066055

RESUMO

Terpenoid-based essential oils are economically important commodities, yet beyond their biosynthetic pathways, little is known about the genetic architecture of terpene oil yield from plants. Transport, storage, evaporative loss, transcriptional regulation and precursor competition may be important contributors to this complex trait. Here, we associate 2.39 million single nucleotide polymorphisms derived from shallow whole-genome sequencing of 468 Eucalyptus polybractea individuals with 12 traits related to the overall terpene yield, eight direct measures of terpene concentration and four biomass-related traits. Our results show that in addition to terpene biosynthesis, development of secretory cavities, where terpenes are both synthesized and stored, and transport of terpenes were important components of terpene yield. For sesquiterpene concentrations, the availability of precursors in the cytosol was important. Candidate terpene synthase genes for the production of 1,8-cineole and α-pinene, and ß-pinene (which comprised > 80% of the total terpenes) were functionally characterized as a 1,8-cineole synthase and a ß/α-pinene synthase. Our results provide novel insights into the genomic architecture of terpene yield and we provide candidate genes for breeding or engineering of crops for biofuels or the production of industrially valuable terpenes.


Assuntos
Eucalyptus/genética , Genoma de Planta , Estudo de Associação Genômica Ampla , Óleos de Plantas/metabolismo , Terpenos/metabolismo , Alquil e Aril Transferases/genética , Vias Biossintéticas , Genes de Plantas , Genótipo , Padrões de Herança/genética , Análise Multivariada , Polimorfismo de Nucleotídeo Único/genética , Locos de Características Quantitativas/genética , Reprodutibilidade dos Testes , Terpenos/química
9.
J Chem Ecol ; 44(1): 51-61, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29376212

RESUMO

Plants that synthesize and store terpenes in specialized cells accumulate large concentrations of these compounds while avoiding autotoxicity. Stored terpenes may influence the quantity and profile of volatile compounds that are emitted into the environment and the subsequent role of those volatiles in mediating the activity of herbivores. The Australian medicinal tea tree, Melaleuca alternifolia, occurs as several distinct terpene chemotypes. We studied the profile of its terpene emissions to understand how variations in stored foliar terpenes influenced emissions, both constitutive and when damaged either by herbivores or mechanically. We found that foliar chemistry influenced differences in the composition of terpene emissions, but those emissions were minimal in intact plants. When plants were damaged by herbivores or mechanically, the emissions were greatly increased and the composition corresponded to the constitutive terpenes and the volatility of each compound, suggesting the main origin of emissions is the stored terpenes and not de novo biosynthesized volatiles. However, herbivores modified the composition of the volatile emissions in only one chemotype, probably due to the oxidative metabolism of 1,8-cineole by the beetles. We also tested whether the foliar terpene blend acted as an attractant for the specialized leaf beetles Paropsisterna tigrina and Faex sp. and a parasitoid fly, Anagonia zentae. None of these species responded to extracts of young leaves in an olfactometer, so we found no evidence that these species use plant odor cues for host location in laboratory conditions.


Assuntos
Besouros/fisiologia , Plantas/química , Terpenos/análise , Compostos Orgânicos Voláteis/química , Animais , Besouros/efeitos dos fármacos , Cicloexanóis/análise , Cicloexanóis/farmacologia , Eucaliptol , Cromatografia Gasosa-Espectrometria de Massas , Herbivoria/efeitos dos fármacos , Interações Hospedeiro-Parasita/efeitos dos fármacos , Monoterpenos/análise , Monoterpenos/farmacologia , Folhas de Planta/química , Folhas de Planta/metabolismo , Folhas de Planta/parasitologia , Plantas/metabolismo , Plantas/parasitologia , Análise de Componente Principal , Terpenos/metabolismo , Terpenos/farmacologia
10.
J Chem Ecol ; 44(1): 62-71, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29209932

RESUMO

Ecologists have long been interested in how the nutritional composition of leaves changes as they age, and whether this affects herbivore feeding preferences. As a consequence, the literature abounds with reports that younger leaves contain higher concentrations of nitrogen and plant secondary metabolites (PSMs) than do older leaves. Most of these studies, however, base their conclusions on average values that often mean little to herbivores. We examined this issue in the well-studied marsupial-eucalypt system, using Eucalyptus melliodora and captive common brushtail possums (Trichosurus vulpecula) offered branches from individual trees containing both young and mature leaves. Like many plants, the concentrations of N and PSMs differed among individual E. melliodora. Although young leaves were, on average, "better defended" by the PSM sideroxylonal than were mature leaves, some trees produced leaves that were relatively undefended at both ages. In response, possums chose different proportions of young and mature leaves depending on the chemistry of the individual tree. Possums did not always prefer leaves with lower concentrations of sideroxylonal (mature leaves) or those with higher concentrations of available N (young leaves). Instead, the sideroxylonal concentration of young leaves dictated their choice: possums preferred young leaves with low sideroxylonal concentrations, but not with high concentrations. By skewing their feeding toward trees producing young leaves with low concentrations of PSMs, possums may influence plant fitness. Researchers will detect these potentially important interactions only if they are aware that measuring variation among plants discloses more information than do average relationships.


Assuntos
Eucalyptus/química , Trichosurus/fisiologia , Animais , Benzofuranos/análise , Benzofuranos/farmacologia , Cromatografia Líquida de Alta Pressão , Eucalyptus/metabolismo , Comportamento Alimentar/efeitos dos fármacos , Herbivoria , Masculino , Nitrogênio/análise , Floroglucinol/análogos & derivados , Floroglucinol/análise , Floroglucinol/farmacologia , Folhas de Planta/química , Folhas de Planta/metabolismo , Fatores de Tempo
11.
Phytopathology ; 108(4): 495-509, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29135360

RESUMO

Plants have developed complex defense mechanisms to protect themselves against pathogens. A wide-host-range fungus, Austropuccinia psidii, which has caused severe damage to ecosystems and plantations worldwide, is a major threat to Australian ecosystems dominated by members of the family Myrtaceae. In particular, the east coast wetland foundation tree species Melaleuca quinquenervia, appears to be variably susceptible to this pathogen. Understanding the molecular basis of host resistance would enable better management of this rust disease. We identified resistant and susceptible individuals of M. quinquenervia and explored their differential gene expression in order to discover the molecular basis of resistance against A. psidii. Rust screening of germplasm showed a varying degree of response, with fully resistant to highly susceptible individuals. We used transcriptome profiling in samples collected before and at 5 days postinoculation (dpi). Differential gene expression analysis showed that numerous defense-related genes were induced in susceptible plants at 5 dpi. Mapping reads against the A. psidii genome showed that only susceptible plants contained fungal-derived transcripts. Resistant plants exhibited an overexpression of candidate A. psidii resistance-related genes such as receptor-like kinases, nucleotide-binding site leucine-rich repeat proteins, glutathione S-transferases, WRKY transcriptional regulators, and pathogenesis-related proteins. We identified large differences in the expression of defense-related genes among resistant individuals.


Assuntos
Basidiomycota/fisiologia , Resistência à Doença/genética , Melaleuca/genética , Doenças das Plantas/imunologia , Transcriptoma , Austrália , Ecossistema , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Melaleuca/imunologia , Melaleuca/microbiologia , Modelos Biológicos , Doenças das Plantas/microbiologia , Folhas de Planta/genética , Folhas de Planta/imunologia , Folhas de Planta/microbiologia , Análise de Sequência de RNA , Árvores
12.
BMC Plant Biol ; 17(1): 160, 2017 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-28978322

RESUMO

BACKGROUND: Terpene rich leaves are a characteristic of Myrtaceae. There is significant qualitative variation in the terpene profile of plants within a single species, which is observable as "chemotypes". Understanding the molecular basis of chemotypic variation will help explain how such variation is maintained in natural populations as well as allowing focussed breeding for those terpenes sought by industry. The leaves of the medicinal tea tree, Melaleuca alternifolia, are used to produce terpinen-4-ol rich tea tree oil, but there are six naturally occurring chemotypes; three cardinal chemotypes (dominated by terpinen-4-ol, terpinolene and 1,8-cineole, respectively) and three intermediates. It has been predicted that three distinct terpene synthases could be responsible for the maintenance of chemotypic variation in this species. RESULTS: We isolated and characterised the most abundant terpene synthases (TPSs) from the three cardinal chemotypes of M. alternifolia. Functional characterisation of these enzymes shows that they produce the dominant compounds in the foliar terpene profile of all six chemotypes. Using RNA-Seq, we investigated the expression of these and 24 additional putative terpene synthases in young leaves of all six chemotypes of M. alternifolia. CONCLUSIONS: Despite contributing to the variation patterns observed, variation in gene expression of the three TPS genes is not enough to explain all variation for the maintenance of chemotypes. Other candidate terpene synthases as well as other levels of regulation must also be involved. The results of this study provide novel insights into the complexity of terpene biosynthesis in natural populations of a non-model organism.


Assuntos
Alquil e Aril Transferases/metabolismo , Melaleuca/enzimologia , Alquil e Aril Transferases/genética , Alquil e Aril Transferases/isolamento & purificação , Monoterpenos Cicloexânicos , Cicloexanóis/metabolismo , DNA de Plantas , Eucaliptol , Perfilação da Expressão Gênica , Genes de Plantas , Melaleuca/química , Melaleuca/genética , Monoterpenos/metabolismo , Análise de Sequência de DNA , Terpenos/metabolismo , Árvores/química , Árvores/enzimologia
13.
Appl Environ Microbiol ; 83(10)2017 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-28314727

RESUMO

Pseudomonas aeruginosa can utilize hydrocarbons, but different strains have various degrees of adaptation despite their highly conserved genome. P. aeruginosa ATCC 33988 is highly adapted to hydrocarbons, while P. aeruginosa strain PAO1, a human pathogen, is less adapted and degrades jet fuel at a lower rate than does ATCC 33988. We investigated fuel-specific transcriptomic differences between these strains in order to ascertain the underlying mechanisms utilized by the adapted strain to proliferate in fuel. During growth in fuel, the genes related to alkane degradation, heat shock response, membrane proteins, efflux pumps, and several novel genes were upregulated in ATCC 33988. Overexpression of alk genes in PAO1 provided some improvement in growth, but it was not as robust as that of ATCC 33988, suggesting the role of other genes in adaptation. Expression of the function unknown gene PA5359 from ATCC 33988 in PAO1 increased the growth in fuel. Bioinformatic analysis revealed that PA5359 is a predicted lipoprotein with a conserved Yx(FWY)xxD motif, which is shared among bacterial adhesins. Overexpression of the putative resistance-nodulation-division (RND) efflux pump PA3521 to PA3523 increased the growth of the ATCC 33988 strain, suggesting a possible role in fuel tolerance. Interestingly, the PAO1 strain cannot utilize n-C8 and n-C10 The expression of green fluorescent protein (GFP) under the control of alkB promoters confirmed that alk gene promoter polymorphism affects the expression of alk genes. Promoter fusion assays further confirmed that the regulation of alk genes was different in the two strains. Protein sequence analysis showed low amino acid differences for many of the upregulated genes, further supporting transcriptional control as the main mechanism for enhanced adaptation.IMPORTANCE These results support that specific signal transduction, gene regulation, and coordination of multiple biological responses are required to improve the survival, growth, and metabolism of fuel in adapted strains. This study provides new insight into the mechanistic differences between strains and helpful information that may be applied in the improvement of bacterial strains for resistance to biotic and abiotic factors encountered during bioremediation and industrial biotechnological processes.


Assuntos
Proteínas de Bactérias/genética , Hidrocarbonetos/metabolismo , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo , Motivos de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Hidrocarbonetos/química , Estrutura Molecular , Regiões Promotoras Genéticas , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/isolamento & purificação
14.
Plant Cell Environ ; 40(10): 2406-2425, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28771760

RESUMO

Plant chemotypes or chemical polymorphisms are defined by discrete variation in secondary metabolites within a species. This variation can have consequences for ecological interactions or the human use of plants. Understanding the molecular basis of chemotypic variation can help to explain how variation of plant secondary metabolites is controlled. We explored the transcriptomes of the 3 cardinal terpene chemotypes of Melaleuca alternifolia in young leaves, mature leaves, and stem and compared transcript abundance to variation in the constitutive profile of terpenes. Leaves from chemotype 1 plants (dominated by terpinen-4-ol) show a similar pattern of gene expression when compared to chemotype 5 plants (dominated by 1,8-cineole). Only terpene synthases in young leaves were differentially expressed between these chemotypes, supporting the idea that terpenes are mainly synthetized in young tissue. Chemotype 2 plants (dominated by terpinolene) show a greater degree of differential gene expression compared to the other chemotypes, which might be related to the isolation of plant populations that exhibit this chemotype and the possibility that the terpinolene synthase gene in M. alternifolia was derived by introgression from a closely related species, Melaleuca trichostachya. By using multivariate analyses, we were able to associate terpenes with candidate terpene synthases.


Assuntos
Perfilação da Expressão Gênica , Melaleuca/genética , Especificidade de Órgãos/genética , Terpenos/metabolismo , Alquil e Aril Transferases/genética , Alquil e Aril Transferases/metabolismo , Austrália , Análise por Conglomerados , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Geografia , Análise dos Mínimos Quadrados , Fatores de Transcrição/metabolismo
15.
J Chem Ecol ; 43(4): 411-421, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28367596

RESUMO

Insect folivores can cause extensive damage to plants. However, different plant species, and even individuals within species, can differ in their susceptibility to insect attack. Polyphenols that readily oxidize have recently gained attention as potential defenses against insect folivores. We tested the hypothesis that variation in oxidizable phenolic concentrations in Eucalyptus foliage influences feeding and survival of Paropsis atomaria (Eucalyptus leaf beetle) larvae. First we demonstrated that oxidizable phenolic concentrations vary both within and between Eucalyptus species, ranging from 0 to 61 mg.g-1 DM (0 to 81% of total phenolics), in 175 samples representing 13 Eucalyptus species. Foliage from six individuals from each of ten species of Eucalyptus were then offered to batches of newly hatched P. atomaria larvae, and feeding, instar progression and mortality of the first and second instar larvae were recorded. Although feeding and survival parameters differed dramatically between individual plants, they were not influenced by the oxidizable phenolic concentration of leaves, suggesting that P. atomaria larvae may have effective mechanisms to deal with oxidizable phenolics. Larvae feeding on plants with higher nitrogen (N) concentrations had higher survival rates and reached third instar earlier, but N concentrations did not explain most of the variation in feeding and survival. The cause of variation in eucalypt herbivory by P. atomaria larvae is therefore still unknown, although oxidizable phenolics could potentially defend eucalypt foliage against other insect herbivores.


Assuntos
Besouros/fisiologia , Eucalyptus/química , Larva/crescimento & desenvolvimento , Larva/metabolismo , Fenóis/análise , Folhas de Planta/química , Animais , Besouros/metabolismo , Ingestão de Alimentos , Eucalyptus/metabolismo , Comportamento Alimentar , Herbivoria , Oxirredução , Fenóis/química , Fenóis/metabolismo , Folhas de Planta/metabolismo , Taninos/química
16.
J Chem Ecol ; 43(9): 944, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28983845

RESUMO

Ian Wallis was inadvertently omitted as an author in this study. Ian Wallis assisted with the collection of the leaf samples that were used in this study, and built the chambers that the insects were housed in.

17.
Am J Primatol ; 79(4): 1-13, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27094926

RESUMO

Protein limitation has been considered a key factor in hypotheses on the evolution of life history and animal communities, suggesting that animals should prioritize protein in their food choice. This contrasts with the limited support that food selection studies have provided for such a priority in nonhuman primates, particularly for folivores. Here, we suggest that this discrepancy can be resolved if folivores only need to select for high protein leaves when average protein concentration in the habitat is low. To test the prediction, we applied meta-analyses to analyze published and unpublished results of food selection for protein and fiber concentrations from 24 studies (some with multiple species) of folivorous primates. To counter potential methodological flaws, we differentiated between methods analyzing total nitrogen and soluble protein concentrations. We used a meta-analysis to test for the effect of protein on food selection by primates and found a significant effect of soluble protein concentrations, but a non-significant effect for total nitrogen. Furthermore, selection for soluble protein was reinforced in forests where protein was less available. Selection for low fiber content was significant but unrelated to the fiber concentrations in representative leaf samples of a given forest. There was no relationship (either negative or positive) between the concentration of protein and fiber in the food or in representative samples of leaves. Overall our study suggests that protein selection is influenced by the protein availability in the environment, explaining the sometimes contradictory results in previous studies on protein selection. Am. J. Primatol. 79:e22550, 2017. © 2016 Wiley Periodicals, Inc.


Assuntos
Comportamento Alimentar , Preferências Alimentares , Folhas de Planta , Primatas , Animais , Fibras na Dieta
18.
J Chem Ecol ; 42(6): 523-32, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27256074

RESUMO

Polyethylene glycol (PEG) has been used to study the intake and digestion of tannin-rich plants by mammalian herbivores because it preferentially binds to tannins. However, it is not clear whether the responses of herbivores to dietary PEG is due to increased protein availability from the release of tannin-bound protein, amelioration of tannin effects, or whether PEG also may bind to other compounds and change their activity in the gut. We used three native New Zealand tree species to measure the effect of PEG on the amount of foliage eaten by invasive common brushtail possums (Trichosurus vulpecula) and on in vitro digestible nitrogen (available N). The addition of PEG increased the in vitro available N content of Weinmannia racemosa foliage, and possums ate significantly more PEG-treated foliage than untreated foliage. However, possums also ate more PEG-treated Fuchsia excorticata foliage, even though PEG did not increase in vitro available N in this species. Possums ate very little Melicytus ramiflorus, regardless of PEG treatment, even though M. ramiflorus contained the highest concentration of in vitro available N. These results prompted us to use PEG and a protein supplement, casein, to manipulate the available N concentration of diets containing ground eucalypt foliage, a well-studied food species for possums. Again, the response of possums to PEG was independent of changes in in vitro available N. In addition, altering the protein content of the diet via the addition of casein did not affect how much food the possums consumed. We conclude that the effects of PEG on dry matter intake by mammalian herbivores are not due solely to the release of tannin-bound protein. There is need for a better understanding of PEG-tannin interactions in order to ensure that the use of PEG in nutritional studies does not outstrip an understanding of its mechanisms of action.


Assuntos
Dieta , Herbivoria/efeitos dos fármacos , Polietilenoglicóis/farmacologia , Animais , Digestão/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Feminino , Masculino , Folhas de Planta/química , Proteínas de Plantas/metabolismo , Taninos/análise , Trichosurus/metabolismo , Trichosurus/fisiologia
19.
BMC Genomics ; 16: 450, 2015 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-26062733

RESUMO

BACKGROUND: Terpenoids are abundant in the foliage of Eucalyptus, providing the characteristic smell as well as being valuable economically and influencing ecological interactions. Quantitative and qualitative inter- and intra- specific variation of terpenes is common in eucalypts. RESULTS: The genome sequences of Eucalyptus grandis and E. globulus were mined for terpene synthase genes (TPS) and compared to other plant species. We investigated the relative expression of TPS in seven plant tissues and functionally characterized five TPS genes from E. grandis. Compared to other sequenced plant genomes, Eucalyptus grandis has the largest number of putative functional TPS genes of any sequenced plant. We discovered 113 and 106 putative functional TPS genes in E. grandis and E. globulus, respectively. All but one TPS from E. grandis were expressed in at least one of seven plant tissues examined. Genomic clusters of up to 20 genes were identified. Many TPS are expressed in tissues other than leaves which invites a re-evaluation of the function of terpenes in Eucalyptus. CONCLUSIONS: Our data indicate that terpenes in Eucalyptus may play a wider role in biotic and abiotic interactions than previously thought. Tissue specific expression is common and the possibility of stress induction needs further investigation. Phylogenetic comparison of the two investigated Eucalyptus species gives insight about recent evolution of different clades within the TPS gene family. While the majority of TPS genes occur in orthologous pairs some clades show evidence of recent gene duplication, as well as loss of function.


Assuntos
Alquil e Aril Transferases/genética , Eucalyptus/enzimologia , Proteínas de Plantas/genética , Alquil e Aril Transferases/metabolismo , Eucalyptus/classificação , Eucalyptus/genética , Evolução Molecular , Genoma de Planta , Família Multigênica , Filogenia , Proteínas de Plantas/metabolismo
20.
Theor Appl Genet ; 128(12): 2351-65, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26239409

RESUMO

The yield of essential oil in commercially harvested perennial species (e.g. 'Oil Mallee' eucalypts, Tea Trees and Hop) is dependent on complex quantitative traits such as foliar oil concentration, biomass and adaptability. These often show large natural variation and some are highly heritable, which has enabled significant gains in oil yield via traditional phenotypic recurrent selection. Analysis of transcript abundance and allelic diversity has revealed that essential oil yield is likely to be controlled by large numbers of quantitative trait loci that range from a few of medium/large effect to many of small effect. Molecular breeding techniques that exploit this information could increase gains per unit time and address complications of traditional breeding such as genetic correlations between key traits and the lower heritability of biomass. Genomic selection (GS) is a technique that uses the information from markers genotyped across the whole genome in order to predict the phenotype of progeny well before they reach maturity, allowing selection at an earlier age. In this review, we investigate the feasibility of genomic selection (GS) for the improvement of essential oil yield. We explore the challenges facing breeders selecting for oil yield, and how GS might deal with them. We then assess the factors that affect the accuracy of genomic estimated breeding values, such as linkage disequilibrium (LD), heritability, relatedness and the genetic architecture of desirable traits. We conclude that GS has the potential to significantly improve the efficiency of selection for essential oil yield.


Assuntos
Produtos Agrícolas/genética , Óleos Voláteis/química , Melhoramento Vegetal/métodos , Seleção Genética , Produtos Agrícolas/química , Eucalyptus , Marcadores Genéticos , Genótipo , Humulus , Desequilíbrio de Ligação , Melaleuca , Fenótipo , Locos de Características Quantitativas
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