Evolutionary and chemical ecology of Verbascum thapsus reveal potential mechanisms of invasion

2011 Fall.Includes bibliographical references.Biological invasions, which occur when introduced species achieve pest status due to dramatic increases in performance, cause substantial environmental and economic damage. Invasion dynamics are extremely complex, varying in space and time, and as a function of the associations that form between introduced species and the biota present in the communities they invade. For plants, herbivores play a central role in shaping the outcome of introduction events. In particular, when plants are introduced to novel ranges, they often leave behind coevolved specialist herbivores (typically insects) that act to suppress populations in the native range. This can lead to increases in plant performance, for example when introduced plants evolving in communities devoid of enemies reallocate resources from defenses to growth and reproduction. Because of the important biological associations that exist between plants and insect herbivores, as well as the dramatic shifts in these associations that characterize biological invasions, this research places a particular emphasis on the evolutionary and chemical ecology of plant-insect interactions. More broadly, this research quantifies several aspects of the invasion dynamics of the introduced weed Verbascum Thapsus L. (Scrophulariaceae, common mullein). I first present data from a biogeographic comparison in which a survey of more than 50 native (European) and introduced (United States) mullein populations confirms a marked increase in population- and plant-level performance in the introduced range. I also document several ecological differences between ranges, including shifts in the abundance, identity, and degree of damage caused by insect herbivores, as well as differences in the abundance and identity of plant competitors and precipitation availability. A greenhouse experiment revealed that the increased performance observed in the field is maintained when native and introduced plants are grown from seed in a common environment; thus, a component of the performance phenotype is genetically based, or evolved. However, this increase in performance is not associated with an evolved decrease in defense investment as predicted by the evolution of increased competitive ability (EICA) hypothesis. Indeed, despite significant population-level variation in several defenses (trichomes, leaf toughness and iridoid glycosides), there is no evidence for the evolution of range-level differences in defense investment. I further explored how mullein's investment in chemical defense varies in natural populations and in relationship to damage by chewing herbivores. Based on this exploration, I developed new predictions for how changes to defense allocation may result in increased performance. Natural mullein populations exposed to ambient levels of herbivory in the introduced range exhibit significant population- and plant-level variation in iridoid glycosides. In particular, young (highly valuable) leaves are more than 6 better defended than old leaves, and likely because of this incur minimal damage from generalist herbivores. The limited ability of generalists to feed on mullein's well-defended young leaves results in negligible losses of high-quality tissue, suggesting a mechanism for mullein's increased performance in North America. Indeed, the within-plant distribution of iridoid glycosides significantly differs between native and introduced plants exposed to the different insect communities present in each range. Importantly, introduced mullein invests significantly more in the chemical defense of valuable young leaves than does native mullein, which leads to a dramatic reduction in the attack of young leaves in the introduced range relative to the native range. This optimization of within-plant investment in defense reflects the fact that introduced mullein has been released from the evolutionary dilemma posed by simultaneous attack by specialist and generalist herbivores (with specialists often being attracted to the same chemicals used to deter generalists from feeding, resulting in stabilizing selection on defense levels). In summary, this research provides evidence for a dramatic increase in the performance of introduced common mullein that is associated with several ecological differences between ranges as well as potentially adaptive shifts in mullein's chemical defense investment under natural conditions

The effect of insect herbivory on the growth and fitness of introduced Verbascum thapsus L.

A majority of the plant species that are introduced into new ranges either do not become established, or become naturalized yet do not attain high densities and are thus considered ecologically and economically unproblematic. The factors that limit these relatively “benign” species are not well studied. The biotic resistance hypothesis predicts that herbivores, pathogens and competition reduce growth and reproduction of individual plants and so suppress population growth of non-native species. We explored the effect of insect herbivory and surrounding vegetation on growth and fitness of the non-native biennial plant Verbascum thapsus (common mullein) in Colorado, USA. Mullein is widespread in its introduced North American range, yet is infrequently considered a management concern because populations are often ephemeral and restricted to disturbed sites. To evaluate the impact of insect herbivores on mullein performance, we reduced herbivory using an insecticide treatment and compared sprayed plants to those exposed to ambient levels of herbivory. Reducing herbivory increased survival from rosette to reproduction by 7%, from 70–77%. Of plants that survived, reducing herbivory increased plant area in the first year and plant height, the length of the reproductive spike, and seed set during the second year. Reducing herbivory also had a marked effect on plant fitness, increasing seed set by 50%, from about 48,000 seeds per plant under ambient herbivory to about 98,000 per plant under reduced herbivory. Our findings also highlight that the relationship between herbivory and performance is complex. Among plants exposed to ambient herbivory, we observed a positive relationship between damage and performance, suggesting that, as predicted by the plant vigor hypothesis, insect herbivores choose the largest plants for feeding when their choice is not restricted by insecticide treatment. In contrast to the strong effects of experimentally reduced herbivory, we found that cover of other plants surrounding our focal plants explained relatively little variation in performance outcomes. Overall, we found that herbivore-induced impacts on individual plant performance and seed set are substantial, and thus may help prevent this naturalized species from becoming dominant in undisturbed recipient communities

Chemical and mechanical defenses vary among maternal lines and leaf ages in Verbascum thapsus L. (Scrophulariaceae) and reduce palatability to a generalist insect

Includes bibliographical references (pages 10-11).Intra-specific variation in host-plant quality affects herbivore foraging decisions and, in turn, herbivore foraging decisions mediate plant fitness. In particular, variation in defenses against herbivores, both among and within plants, shapes herbivore behavior. If variation in defenses is genetically based, it can respond to natural selection by herbivores. We quantified intra-specific variation in iridoid glycosides, trichome length, and leaf strength in common mullein (Verbascum thapsus L, Scrophulariaceae) among maternal lines within a population and among leaves within plants, and related this variation to feeding preferences of a generalist herbivore, Trichopulsia ni Hübner. We found significant variation in all three defenses among maternal lines, with T. ni preferring plants with lower investment in chemical, but not mechanical, defense. Within plants, old leaves had lower levels of all defenses than young leaves, and were strongly preferred by T. ni. Caterpillars also preferred leaves with trichomes removed to leaves with trichomes intact. Differences among maternal lines indicate that phenotypic variation in defenses likely has a genetic basis. Furthermore, these results reveal that the feeding behaviors of T. ni map onto variation in plant defense in a predictable way. This work highlights the importance of variation in host-plant quality in driving interactions between plants and their herbivores.Published with support from the Colorado State University Libraries Open Access Research and Scholarship Fund

Electrochemical Stability of Rhodium-Platinum Core-Shell Nanoparticles : An Identical Location Scanning Transmission Electron Microscopy Study

Rhodium-platinum core-shell nanoparticles on a carbon support (Rh@Pt/C NPs) are promising candidates as anode catalysts for polymer electrolyte membrane fuel cells. However, their electrochemical stability needs to be further explored for successful application in commercial fuel cells. Here we employ identical location scanning transmission electron microscopy to track the morphological and compositional changes of Rh@Pt/C NPs during potential cycling (10 000 cycles, 0.06-0.8 V, 0.5 HSO) down to the atomic level, which are then used for understanding the current evolution occurring during the potential cycles. Our results reveal a high stability of the Rh@Pt/C system and point toward particle detachment from the carbon support as the main degradation mechanism

Homologous Recombination Deficiency Across Subtypes of Primary Breast Cancer

Homologous recombination; Primary breast cancerRecombinació homòloga; Càncer de mama primariRecombinación homóloga; Cáncer de mama primarioPURPOSE Homologous recombination deficiency (HRD) is highly prevalent in triple-negative breast cancer (TNBC) and associated with response to PARP inhibition (PARPi). Here, we studied the prevalence of HRD in non-TNBC to assess the potential for PARPi in a wider group of patients with breast cancer. METHODS HRD status was established using targeted gene panel sequencing (360 genes) and BRCA1 methylation analysis of pretreatment biopsies from 201 patients with primary breast cancer in the phase II PETREMAC trial (ClinicalTrials.gov identifier: NCT02624973). HRD was defined as mutations in BRCA1, BRCA2, BRIP1, BARD1, or PALB2 and/or promoter methylation of BRCA1 (strict definition; HRD-S). In secondary analyses, a wider definition (HRD-W) was used, examining mutations in 20 additional genes. Furthermore, tumor BRCAness (multiplex ligation-dependent probe amplification), PAM50 subtyping, RAD51 nuclear foci to test functional HRD, tumor-infiltrating lymphocyte (TIL), and PD-L1 analyses were performed. RESULTS HRD-S was present in 5% of non-TNBC cases (n = 9 of 169), contrasting 47% of the TNBC tumors (n = 15 of 32). HRD-W was observed in 23% of non-TNBC (n = 39 of 169) and 59% of TNBC cases (n = 19 of 32). Of 58 non-TNBC and 30 TNBC biopsies examined for RAD51 foci, 4 of 4 (100%) non-TNBC and 13 of 14 (93%) TNBC cases classified as HRD-S had RAD51 low scores. In contrast, 4 of 17 (24%) non-TNBC and 15 of 19 (79%) TNBC biopsies classified as HRD-W exhibited RAD51 low scores. Of nine non-TNBC tumors with HRD-S status, only one had a basal-like PAM50 signature. There was a high concordance between HRD-S and either BRCAness, high TIL density, or high PD-L1 expression (each P < .001). CONCLUSION The prevalence of HRD in non-TNBC suggests that therapy targeting HRD should be evaluated in a wider breast cancer patient population. Strict HRD criteria should be implemented to increase diagnostic precision with respect to functional HRD.Supported by unrestricted grants from The K.G. Jebsen Foundation [SKGJ-MED-020 to H.P.E., S.K., P.E.L.], Helse Vest [912008 to P.E.L.], The Norwegian Research Council [273354 to P.E.L.] and The Norwegian Cancer Society [190281-2017 to S.K., 190275-2017 to P.E.L.]. Research funding was provided by Grieg Foundation (to H.P.E. and T.A.), Helse Vest [912252; Clinical researcher fellowship to H.P.E.], Generalitat de Catalunya [PERIS, SLT017/20/000081 to A.H.R.], “la Caixa” Foundation and European Institute of Innovation and Technology/Horizon 2020 [LCF/TR/CC19/52470003 to A.L.G.], Asociación Española Contra el Cáncer [AECC, INVES20095LLOP to A.L.G.], Generalitat de Catalunya (PERIS Fellowship SLT002/16/00477 to A.L.G.) ERA PerMed [2019-215 to V.S.] and Miguel Servet fellowship (CPII19/00033 to V.S.). Additional funding and study medication was provided by Illumina [grant number 9529854], Pfizer [WI206347] and AstraZeneca [ESR-14-10077] to H.P.E., S.K., P.E.L

Rare Genetic Variation in 135 Families With Family History Suggestive of X-Linked Intellectual Disability.

Families with multiple male children with intellectual disability (ID) are usually suspected of having disease due to a X-linked mode of inheritance and genetic studies focus on analysis of segregating variants in X-linked genes. However, the genetic cause of ID remains elusive in approximately 50% of affected individuals. Here, we report the analysis of next-generation sequencing data in 274 affected individuals from 135 families with a family history suggestive of X-linked ID. Genetic diagnoses were obtained for 19% (25/135) of the families, and 24% (33/135) had a variant of uncertain significance. In 12% of cases (16/135), the variants were not shared within the family, suggesting genetic heterogeneity and phenocopies are frequent. Of all the families with reportable variants (43%, 58/135), we observed that 55% (32/58) were in X-linked genes, but 38% (22/58) were in autosomal genes, while the remaining 7% (4/58) had multiple variants in genes with different modes on inheritance. This study highlights that in families with multiple affected males, X linkage should not be assumed, and both individuals should be considered, as different genetic etiologies are common in apparent familial cases

Impact of Industrial Practices on the Microbial and Quality Attributes of Fresh Vacuum-Packed Lamb Joints

The impact of different industrial practices at lamb export abattoirs in Ireland on the microbial and quality attributes of fresh vacuum-packed (VP) lamb leg joints, including Clean Livestock Policy (CLP), fleece clipping, carcass chilling times and vacuum pack storage, at typical chill and retail display temperatures was investigated. Five separate slaughter batches of lamb (ranging in size from 38 to 60 lambs) were followed at two lamb export plants over a two-year period, accounting for seasonal variation. In general, fleece clipping resulted in significantly lower microbial contamination on the fleece than the use of CLP alone. Lamb from carcasses chilled for 24 h had significantly lower psychrophilic total viable counts and Brochothrix thermosphacta and pseudomonad counts than carcasses chilled for 72 h. Following vacuum-packed (VP) storage of meat from these carcasses at 1.7 1.6 C for 23 days in the meat plant followed by retail display at 3.9 1.7 C (up to day 50), the dominant microorganisms were lactic acid bacteria, Br. thermosphacta, Enterobacteriaceae and pseudomonads, and all had reached maximum population density by storage day 34. Aligned with this, after day 34, the quality of the raw meat samples also continued to deteriorate, with off-odors and color changes developing. While the mean values for cooked meat eating quality attributes did not change significantly over the VP storage period, high variability in many attributes, including off-flavors and off-odors, were noted for lamb meat from all storage times, highlighting inconsistences in lamb quality within and between slaughter batches

The Central Nervous System Contains ILC1s That Differ From NK Cells in the Response to Inflammation

Innate lymphoid cells (ILCs) are tissue resident cells with organ-specific properties. Here, we show that the central nervous system (CNS) encompasses ILCs. In particular, CD3-NK1.1+ cells present in the murine CNS comprise natural killer (NK) cells, ILC1s, intermediate ILC1s (intILC1s) and ex-ILC3s. We investigated the properties of CNS-ILC1s in comparison with CNS-NK cells during steady state and experimental autoimmune encephalomyelitis (EAE). ILC1s characteristically express CXCR3, CXCR6, DNAM-1, TRAIL, and CD200R and display heightened TNF-α production upon stimulation. In addition, ILC1s express perforin and are able to degranulate, although in a lesser extent than NK cells. Within the CNS compartments, ILC1s are enriched in the choroid plexus where very few NK cells are present, and also reside in the brain parenchyma and meninges. During EAE, ILC1s maintain stable IFN-γ and TNF-α levels while in NK cells the production of these cytokines increases as EAE progresses. Moreover, the amount of ILC1s and intILC1s increase in the parenchyma during EAE, but in contrast to NK cells, they show no signs of local proliferation. The upregulation in the inflamed brain of chemokines involved in ILC1 migration, such as CXCL9, CXCL10, and CXCL16 may lead to a recruitment of ILC1s from meninges or choroid plexus into the brain parenchyma. In sum, CNS-ILC1 phenotype, distribution and moderate inflammatory response during EAE suggest that they may act as gatekeepers involved in the control of neuroinflammation

IDOL regulates systemic energy balance through control of neuronal VLDLR expression.

Liver X receptors limit cellular lipid uptake by stimulating the transcription of Inducible Degrader of the LDL Receptor (IDOL), an E3 ubiquitin ligase that targets lipoprotein receptors for degradation. The function of IDOL in systemic metabolism is incompletely understood. Here we show that loss of IDOL in mice protects against the development of diet-induced obesity and metabolic dysfunction by altering food intake and thermogenesis. Unexpectedly, analysis of tissue-specific knockout mice revealed that IDOL affects energy balance, not through its actions in peripheral metabolic tissues (liver, adipose, endothelium, intestine, skeletal muscle), but by controlling lipoprotein receptor abundance in neurons. Single-cell RNA sequencing of the hypothalamus demonstrated that IDOL deletion altered gene expression linked to control of metabolism. Finally, we identify VLDLR rather than LDLR as the primary mediator of IDOL effects on energy balance. These studies identify a role for the neuronal IDOL-VLDLR pathway in metabolic homeostasis and diet-induced obesity

Cross-sectional associations between mothers and children’s breakfast routine : the Feel4Diabetes study

Positive influences of family members have been associated with a high probability of children's daily breakfast consumption. Therefore, the aim of this study was to scrutinize the association of breakfast routines between mothers and their children. The baseline data of the Feel4Diabetes-study was obtained in 9760 children (49.05% boys)-mother pairs in six European countries. A parental self-reported questionnaire gauging the frequency of breakfast consumption and of breakfast ' foods and beverages consumption was used. Agreement in routines of mothers and their children's breakfast consumption was analyzed in sex-specific crosstabs. The relationship of breakfast routine and food groups' consumption between mothers and their children was assessed with analysis of covariance. The highest proportion of children who always consumed breakfast were those whose mothers always consumed it. Children consuming breakfast regularly had a higher intake of milk or unsweetened dairy products and all kind of cereal products (low fiber and whole-grain) than occasional breakfast consumers (p < 0.05). The strong similarity between mothers and children suggests a transfer of breakfast routine from mothers to their children, as a high proportion of children who usually consume breakfast were from mothers also consuming breakfast. All breakfast foods and beverages consumption frequencies were similar between children and their mothers