Multiple and contrasting pressures determine intraspecific phytochemical variation in a tropical shrub.

Intraspecific phytochemical variation across a landscape can cascade up trophic levels, potentially mediating the composition of entire insect communities. Surprisingly, we have little understanding of the processes that regulate and maintain phytochemical variation within species, likely because these processes are complex and operate simultaneously both temporally and spatially. To assess how phytochemistry varies within species, we tested the degree to which resource availability, contrasting soil type, and herbivory generate intraspecific chemical variation in growth and defense of the tropical shrub, Piper imperiale (Piperaceae).

New Nostocyclophanes from .

Six new nostocyclophanes and four known compounds have been isolated from (Nostocaceae) cyanobacterial strain UTEX B1932. The new compounds, nostocyclophanes E-J (-), were characterized by NMR and MS techniques. The known compounds were nostocyclophanes B-D, previously isolated from this strain, and dedichloronostocyclophane D.

Discovery of octopamine and tyramine in nectar and their effects on bumblebee behavior.

Nectar chemistry can influence the behavior of pollinators in ways that affect pollen transfer, yet basic questions about how nectar chemical diversity impacts plant-pollinator relationships remain unexplored. For example, plants' capacity to produce neurotransmitters and endocrine disruptors may offer a means to manipulate pollinator behavior. We surveyed 15 plant species and discovered that two insect neurotransmitters, octopamine and tyramine, were widely distributed in floral nectar.

The chemical ecology of tropical forest diversity: Environmental variation, chemical similarity, herbivory, and richness.

Species richness in tropical forests is correlated with other dimensions of diversity, including the diversity of plant-herbivore interactions and the phytochemical diversity that influences those interactions. Understanding the complexity of plant chemistry and the importance of phytochemical diversity for plant-insect interactions and overall forest richness has been enhanced significantly by the application of metabolomics to natural systems. The present work used proton nuclear magnetic resonance spectroscopy ( H-NMR) profiling of crude leaf extracts to study phytochemical similarity and diversity among Piper plants growing naturally in the Atlantic Rainforest of Brazil.

Phytochemistry reflects different evolutionary history in traditional classes versus specialized structural motifs.

Foundational hypotheses addressing plant-insect codiversification and plant defense theory typically assume a macroevolutionary pattern whereby closely related plants have similar chemical profiles. However, numerous studies have documented variation in the degree of phytochemical trait lability, raising the possibility that phytochemical evolution is more nuanced than initially assumed. We utilize proton nuclear magnetic resonance (H NMR) data, chemical classification, and double digest restriction-site associated DNA sequencing (ddRADseq) to resolve evolutionary relationships and characterize the evolution of secondary chemistry in the Neotropical plant clade Radula (Piper; Piperaceae).

Opposing Effects of Phytochemistry on Herbivore Communities at Multiple Scales.

Identifying the interactions of functional, biotic, and abiotic factors that define plant-insect communities has long been a goal of community ecologists. Metabolomics approaches facilitate a broader understanding of how phytochemistry mediates the functional interactions among ecological factors. communities are a relatively unstudied system for investigating chemically mediated interactions.

Predicting patch occupancy reveals the complexity of host range expansion.

Specialized plant-insect interactions are a defining feature of life on earth, yet we are only beginning to understand the factors that set limits on host ranges in herbivorous insects. To better understand the recent adoption of alfalfa as a host plant by the Melissa blue butterfly, we quantified arthropod assemblages and plant metabolites across a wide geographic region while controlling for climate and dispersal inferred from population genomic variation. The presence of the butterfly is successfully predicted by direct and indirect effects of plant traits and interactions with other species.

Caterpillars on a phytochemical landscape: The case of alfalfa and the Melissa blue butterfly.

Modern metabolomic approaches that generate more comprehensive phytochemical profiles than were previously available are providing new opportunities for understanding plant-animal interactions. Specifically, we can characterize the phytochemical landscape by asking how a larger number of individual compounds affect herbivores and how compounds covary among plants. Here we use the recent colonization of alfalfa () by the Melissa blue butterfly () to investigate the effects of indivdiual compounds and suites of covarying phytochemicals on caterpillar performance.

Tolyporphins L-R: Unusual Tetrapyrroles from a sp. of Cyanobacterium.

Tolyporphins L-R (-) have been isolated from a mixed cyanobacterium-microbial culture. The structures of tolyporphins L and M have been revised to four constitutional isomers, isolated as two mixtures of dioxobacteriochlorins (/ and /). In contrast, tolyporphin P () is a fully oxidized tetrapyrrole, while tolyporphins Q and R ( and ) are oxochlorins.

Host plant-dependent effects of microbes and phytochemistry on the insect immune response.

Herbivorous insects can defend themselves against pathogens via an immune response, which is influenced by the nutritional quality and phytochemistry of the host plant. However, it is unclear how these aspects of diet interact to influence the insect immune response and what role is played by ingested foliar microbes. We examined dietary protein, phytochemistry, and the caterpillar microbiome to understand variation in immune response of the Melissa blue butterfly, Lycaeides melissa.

Genomic evidence of genetic variation with pleiotropic effects on caterpillar fitness and plant traits in a model legume.

Plant-insect interactions are ubiquitous, and have been studied intensely because of their relevance to damage and pollination in agricultural plants, and to the ecology and evolution of biodiversity. Variation within species can affect the outcome of these interactions. Specific genes and chemicals that mediate these interactions have been identified, but genome- or metabolome-scale studies might be necessary to better understand the ecological and evolutionary consequences of intraspecific variation for plant-insect interactions.

Proximity to canopy mediates changes in the defensive chemistry and herbivore loads of an understory tropical shrub, Piper kelleyi.

Phytochemical traits are a key component of plant defense theory. Chemical ecology has been biased towards studying effects of individual metabolites even though effective plant defenses are comprised of diverse mixtures of metabolites. We tested the phytochemical landscape hypothesis, positing that trophic interactions are contingent upon their spatial location across a phytochemically diverse landscape.

Similarity in volatile communities leads to increased herbivory and greater tropical forest diversity.

A longstanding paradigm in ecology is that there are positive associations between herbivore diversity, specialization, and plant species diversity, with a focus on taxonomic diversity. However, phytochemical diversity is also an informative metric, as insect herbivores interact with host plants not as taxonomic entities, but as sources of nutrients, primary metabolites, and mixtures of attractant and repellant chemicals. The present research examines herbivore responses to phytochemical diversity measured as volatile similarity in the tropical genus Piper.

Resolution of diastereomeric flavonoid (1S)-(-)-camphanic acid esters via reversed-phase HPLC.

Prenylflavonoids are an unique class of phytochemicals found in the inflorescences of the hop plant (Humulus lupulus). These flavonoids have demonstrated a wide range of biological activities, which may be influenced by their stereochemical configuration. Additionally, recent studies suggest that hop prenylflavonoids are subject to biotransformations which could alter or enrich their stereochemistry.

Double-blind evaluation of buprenorphine hydrochloride for post-operative pain.

In a double-blind, random assignment study of four groups of 40 patients, relief of severe pain with buprenorphine hydrochloride 0.2 mg or 0.4 mg was evaluated and compared with morphine sulphate 5 or 10 mg.