A Model of Simultaneous Evolution of Competitive Ability and Herbivore Resistance in a Perennial Plant

Plant populations often experience the joint effects of intraspecific competition and herbivory, yet the impact of the interaction of these two factors on the outcome of evolution is largely unknown. Here, we develop a spatially explicit simulation model to examine interactions between the evolution of herbivore resistance and competitive ability in the goldenrod Solidago altissima. We define competitive ability as either competitive effect, the ability of a plant to deplete resources and make them unavailable to competitors, or competitive response, the ability to grow, survive, and reproduce despite depletion of resources by neighboring competitors. We considered symmetric and asymmetric modes of competition and explored the following questions: (1) Does the selective effect of competition differ for the two components of competitive ability? (2) What are the effects of the evolution of competitive ability and resistance on each other? (3) Can trade-offs between competitive ability and resistance emerge, given no relationship between these two traits prior to selection? Our results showed that competitive response evolved quickly regardless of the mode of competition, but self-suppression hindered the evolution of competitive effect. The evolution of resistance appeared to be independent of the evolution of competitive ability. Intraspecific competition was the major selective force in our model. At natural levels of herbivory, selection for resistance played a secondary role in structuring the population. Resistant genotypes were only favored at very low resistance costs. At high cost levels, the costs of maintaining resistance far outweighed the benefits. The selective forces of competition and herbivory resulted in trade-offs between competitive response and herbivore resistance, but only at low costs of resistance. Vigorous growth associated with a high competitive response might translate into trade-offs between herbivore tolerance and resistance. The strong selective effects of competitors, coupled with the weaker selection from herbivores, suggest that plant traits directly associated with growth that confer tolerance to both competitors and consumers may be the targets of selection

Cardiovascular outcomes following a respiratory tract infection among adults with non-CF bronchiectasis: a general population based study

Rationale: Studies suggest that people with bronchiectasis are at increased risk of cardiovascular co-morbidities. Objectives: We aimed to quantify the relative risk of incident cardiovascular events following a respiratory tract infection amongst people with bronchiectasis. Methods: Using UK electronic primary care records, we conducted a within-person comparison using the self-controlled case series method. We calculated the relative risk of first time cardiovascular events (either first myocardial infarction [MI] or stroke) following a respiratory tract infection compared with the individual’s baseline risk. Results: Our cohort consisted of 895 individuals with non-CF bronchiectasis with a first MI or stroke and at least one respiratory tract infection. There was an increased rate of first time cardiovascular events in the 91 day period after a respiratory tract infection (Incidence Rate Ratio [IRR] 1.56; 95% CI 1.20 to 2.02). The rate of a first cardiovascular event was highest in the first three days following a respiratory tract infection (IRR 2.73, 95% CI 1.41 to 5.27). Conclusions: These data suggest that respiratory tract infections are strongly associated with a transient increased risk of first time MI or stroke amongst people with bronchiectasis. As respiratory tract infections are six times more common in people with bronchiectasis than the general population, the increased risk has a disproportionately greater impact in these individuals. These findings may have implications for including cardiovascular risk modifications in airway infection treatment pathways in this population

Influenza Infection in Wild Raccoons

Raccoons can transmit avian and human influenza Influenza Infection in Wild Raccoon

CRF-Like Diuretic Hormone Negatively Affects Both Feeding and Reproduction in the Desert Locust, Schistocerca gregaria

Diuretic hormones (DH) related to the vertebrate Corticotropin Releasing Factor (CRF) have been identified in diverse insect species. In the migratory locust, Locusta migratoria, the CRF-like DH (CRF/DH) is localized in the same neurosecretory cells as the Ovary Maturating Parsin (OMP), a neurohormone that stimulates oocyte growth, vitellogenesis and hemolymph ecdysteroid levels in adult female locusts. In this study, we investigated whether CRF-like DH can influence feeding and reproduction in the desert locust, Schistocerca gregaria. We identified two highly similar S. gregaria CRF-like DH precursor cDNAs, each of which also encodes an OMP isoform. Alignment with other insect CRF-like DH precursors shows relatively high conservation of the CRF/DH sequence while the precursor region corresponding to OMP is not well conserved. Quantitative real-time RT-PCR revealed that the precursor transcripts mainly occur in the central nervous system and their highest expression level was observed in the brain. Injection of locust CRF/DH caused a significantly reduced food intake, while RNAi knockdown stimulated food intake. Therefore, our data indicate that CRF-like DH induces satiety. Furthermore, injection of CRF/DH in adult females retarded oocyte growth and caused lower ecdysteroid titers in hemolymph and ovaries, while RNAi knockdown resulted in opposite effects. The observed effects of CRF/DH may be part of a wider repertoire of neurohormonal activities, constituting an integrating control system that affects food intake and excretion, as well as anabolic processes like oocyte growth and ecdysteroidogenesis, following a meal. Our discussion about the functional relationship between CRF/DH and OMP led to the hypothesis that OMP may possibly act as a monitoring peptide that can elicit negative feedback effects

Functional genomics reveals serine synthesis is essential in PHGDH-amplified breast cancer

Cancer cells adapt their metabolic processes to drive macromolecular biosynthesis for rapid cell growth and proliferation[superscript 1, 2]. RNA interference (RNAi)-based loss-of-function screening has proven powerful for the identification of new and interesting cancer targets, and recent studies have used this technology in vivo to identify novel tumour suppressor genes[superscript 3]. Here we developed a method for identifying novel cancer targets via negative-selection RNAi screening using a human breast cancer xenograft model at an orthotopic site in the mouse. Using this method, we screened a set of metabolic genes associated with aggressive breast cancer and stemness to identify those required for in vivo tumorigenesis. Among the genes identified, phosphoglycerate dehydrogenase (PHGDH) is in a genomic region of recurrent copy number gain in breast cancer and PHGDH protein levels are elevated in 70% of oestrogen receptor (ER)-negative breast cancers. PHGDH catalyses the first step in the serine biosynthesis pathway, and breast cancer cells with high PHGDH expression have increased serine synthesis flux. Suppression of PHGDH in cell lines with elevated PHGDH expression, but not in those without, causes a strong decrease in cell proliferation and a reduction in serine synthesis. We find that PHGDH suppression does not affect intracellular serine levels, but causes a drop in the levels of α-ketoglutarate, another output of the pathway and a tricarboxylic acid (TCA) cycle intermediate. In cells with high PHGDH expression, the serine synthesis pathway contributes approximately 50% of the total anaplerotic flux of glutamine into the TCA cycle. These results reveal that certain breast cancers are dependent upon increased serine pathway flux caused by PHGDH overexpression and demonstrate the utility of in vivo negative-selection RNAi screens for finding potential anticancer targets.Susan G. Komen Breast Cancer Foundation (Fellowship)Life Sciences Research Foundation (Fellowship)W. M. Keck FoundationDavid H. Koch Cancer Research FundAlexander and Margaret Stewart TrustNational Institutes of Health (U.S.) (Grant CA103866

Using Satellite Tracking to Optimize Protection of Long-Lived Marine Species: Olive Ridley Sea Turtle Conservation in Central Africa

Tractable conservation measures for long-lived species require the intersection between protection of biologically relevant life history stages and a socioeconomically feasible setting. To protect breeding adults, we require knowledge of animal movements, how movement relates to political boundaries, and our confidence in spatial analyses of movement. We used satellite tracking and a switching state-space model to determine the internesting movements of olive ridley sea turtles (Lepidochelys olivacea) (n = 18) in Central Africa during two breeding seasons (2007-08, 2008-09). These movements were analyzed in relation to current park boundaries and a proposed transboundary park between Gabon and the Republic of Congo, both created to reduce unintentional bycatch of sea turtles in marine fisheries. We additionally determined confidence intervals surrounding home range calculations. Turtles remained largely within a 30 km radius from the original nesting site before departing for distant foraging grounds. Only 44.6 percent of high-density areas were found within the current park but the proposed transboundary park would incorporate 97.6 percent of high-density areas. Though tagged individuals originated in Gabon, turtles were found in Congolese waters during greater than half of the internesting period (53.7 percent), highlighting the need for international cooperation and offering scientific support for a proposed transboundary park. This is the first comprehensive study on the internesting movements of solitary nesting olive ridley sea turtles, and it suggests the opportunity for tractable conservation measures for female nesting olive ridleys at this and other solitary nesting sites around the world. We draw from our results a framework for cost-effective protection of long-lived species using satellite telemetry as a primary tool