Effects of the Exotic Red Imported Fire Ant (Solenopsis invicta) on the Growth and Survival of the Threatened Hooded Pitcher Plant (Sarracenia minor)

Plants and insects are some of the most biodiverse groups in the world and are constantly interacting. One unique interaction that has been observed occurs between carnivorous plants and insects; some plant species are capable of capturing and digesting insects for nutrients. Despite preying on these insects, there are cases where such interactions can been viewed as mutualistic. For instance, a nectar reward is produced by the plant to attract insects, and during visitation insects may fall prey to these plants. Additionally, carnivorous myrmecophytic plants may receive an added indirect benefit in the form of reduced herbivory, since ants have the ability to indirectly protect and drive off herbivores from the plant. However, this type of indirect defensive benefit has been rarely observed in carnivorous plants. To determine the nature of the relationship between carnivorous plants and ants, a predator-exclusion experiment was performed in situ using a natural population of the hooded pitcher plant, Sarracenia minor. The presence of the red imported fire ant, Solenopsis invicta, was manipulated in the pitcher plant population to determine if the presence of this non-native ant affects the survival and growth of this carnivorous pitcher plant. From June-November 2014 mean pitcher height and width, number of pitchers, and proportion of pitchers with herbivory present was recorded monthly. Results indicated that pitcher width (p = .042) and the number of pitchers (p = .038) was significantly lower when the presence of S. invicta was reduced. Specifically, the limited presence of S. invicta led to a 21% reduction in mean number of pitchers and a 2.2% reduction in mean pitcher width. This indicated that this non-native ant does provide a direct nutritional benefit for the plant. However, the presence of the ant had no effect on pitcher height and the proportion of pitchers with herbivory present. But, when the proportion of pitchers with herbivory present was compared to a previous native ant study, herbivory proportions where similar or lower when taking the number of ants present into account. This suggests that this non-native ant and native ants equally provide defensive benefits for this native threatened species. Overall, this studied illustrated that carnivorous plants may exhibit similar multiple benefits from a single interaction with a non-native insect that is both prey and provides defense against herbivores

Increasing The Agronomic And Economic Value Of Chickpea And Pea

Domestication has had a profound global impact on human history and a wide range of plants. Understanding the advertent and inadvertent effects of domestication on crops has been instrumental in bolstering food security efforts. For instance, by identifying and re-incorporating lost genotypic variation due to domestication, we can increase crop tolerance to biotic and abiotic stressors. With changing climatic conditions and the ever-growing human population, it has become more imperative to increase and fortify agricultural production. My dissertation addresses this topic in two agronomically important legumes: chickpea (Cicer arietinum) and pea (Pisum sativum). My research aims to increase the agronomic and economic value of these legumes to facilitate agricultural production as well as lessen financial burdens to farmers. To accomplish this aim, in chickpea, we identified the physiological and genetic basis of the green-seed market type and identified the effects of domestication on the response to a novel environment. Furthermore, in pea, we investigated phenotypic variation for cover cropping traits using wild accessions, landraces, and modern varieties. In chickpea, we identified that green-seeded chickpea market type was due to a loss of function mutation of the CaStGR1 (carietinum stay-green gene 1) gene involved in chlorophyll catabolism. Additionally, physiological testing in drought conditions revealed this phenotype to be of the “cosmetic” and not the “functional \u27\u27 stay-green variety. Furthermore, nutritional analysis revealed that this trait was associated with a 2-3 fold increase in provitaminogenic carotenoids that are important for human nutrition. Therefore, this green-seeded trait may increase both the economic and nutritional value of chickpea. To identify how domestication has affected chickpea response to novel environments, we took a whole-plant approach and measured above- and below-ground response to increased nitrogen presence in chickpea. Results revealed that domestication has canalized domesticated chickpea response to nitrogen-rich environments. Furthermore, the variable response of wild chickpea to nitrogen illustrated the need for the use of a comprehensive assortment of wild relative accessions to fully discern the effects of domestication on domesticated organisms. Lastly, we coined the terms “rotational” and “intercropping value” and provide a mathematical equation to quantify these terms. We also discuss numerous methods on how to increase these values. To demonstrate these ideas, we measured the rotational values of domesticated and wild pea. We identified that rotational values and cover-cropping traits such as nutrient mobilization and microbial recruitment vary within field pea. These results indicate that field pea could potentially be improved as a rotational partner and that the use of wild relatives in cover cropping research, which has been underutilized, should be considered. Overall, these results illustrate the importance of understanding the effects of domestication and highlights the importance of crop wild relatives as phenotypic reservoirs for crop improvement. Collectively, my research provides insightful information that can facilitate agricultural production at the farming and breeding level

Morphometric differences in the grasshopper Cornops aquaticum (Bruner, 1906) from South America and South Africa

The semi-aquatic grasshopper Cornops aquaticum is native to South America and inhabits lowlands from southern Mexico to Central Argentina and Uruguay. It is host-specific to aquatic plants in the genera Eichhornia and Pontederia. A quarantine population has existed in South Africa for 10 y, and it is planned to release it there as a biological control agent of water hyacinth, E. crassipes. Various studies of C. aquaticum are coordinated under HICWA (www.mpil-ploen.mpg.de). This paper compares the morphometry of the release population and 11 native populations in South America. We tested four hypotheses: 1) South African and South American populations of C. aquaticum differ in morphology; 2) the South African laboratory population is more similar to other isolated populations in South America than to nonisolated populations; 3) morphology differs across sites; 4) morphology differs with host plant. South African populations differed from continental nonisolated populations, but not from continental isolated ones. Isolated populations presented smaller individuals than nonisolated, but there was also a change in male morphology: while in nonisolated populations male wing length was similar to their body length, in isolated populations, male wings were smaller than body length. Females were larger when on Eicchornia azurea than on E. crassipes, while males presented larger wings than their body on E. azurea, and similar lengths on E. crassipes. These morphological changes may have resulted from phenotypic plasticity, selection for small size, or because of a loss of genetic diversity in quantitative traits.Fil: Adis, Joachim. Institute for Limnology; AlemaniaFil: Sperber, Carlos F. Universidade Federal de Viçosa; BrasilFil: Brede, Edward G. Institute for Limnology; AlemaniaFil: Capello, Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Franceschini, Maria Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Hill, Martin. Rhodes University; SudáfricaFil: Lhano, Marcos G. Universidade Federal de Viçosa; BrasilFil: Marques, Marinê. A;z M.. Universidade Federal de Mato Grosso; BrasilFil: Nunes, Ana L.. Muséu Paraense Emílio Goeldi; BrasilFil: Polar, Perry. CAB International; Trinidad y Tobag

Hydrosulfide (HS⁻) recognition and sensing in water by halogen bonding hosts

Hydrogen sulfide (H₂S) plays a crucial signalling role in a variety of physiological systems, existing as the hydrosulfide anion (HS⁻) at physiological pH. Combining the potency of halogen bonding (XB) for anion recognition in water with coumarin fluorophore incorporation in acyclic host structural design, the first XB receptors to bind and, more importantly, sense the hydrosulfide anion in pure water in a reversible chemosensing fashion are demonstrated. The XB receptors exhibit characteristic selective quenching of fluorescence upon binding to HS⁻. Computational DFT and molecular dynamics simulations in water corroborate the experimental anion binding observations, revealing the mode and nature of HS⁻ recognition by the XB receptors.publishe

Pod shattering: A homologous series of variation underlying domestication and an avenue for crop improvement

All rights reserved. In wild habitats, fruit dehiscence is a critical strategy for seed dispersal; however, in cultivated crops it is one of the major sources of yield loss. Therefore, indehiscence of fruits, pods, etc., was likely to be one of the first traits strongly selected in crop domestication. Even with the historical selection against dehiscence in early domesticates, it is a trait still targeted in many breeding programs, particularly in minor or underutilized crops. Here, we review dehiscence in pulse (grain legume) crops, which are of growing importance as a source of protein in human and livestock diets, and which have received less attention than cereal crops and the model plant Arabidopsis thaliana. We specifically focus on the (i) history of indehiscence in domestication across legumes, (ii) structures and the mechanisms involved in shattering, (iii) the molecular pathways underlying this important trait, (iv) an overview of the extent of crop losses due to shattering, and the effects of environmental factors on shattering, and, (v) efforts to reduce shattering in crops. While our focus is mainly pulse crops, we also included comparisons to crucifers and cereals because there is extensive research on shattering in these taxa

ABCD transfer matrix model of Gaussian beam propagation in Fabry-Perot etalons

A numerical model of Gaussian beam propagation in planar Fabry-Perot (FP) etalons is presented. The model is based on the ABCD transfer matrix method. This method is easy to use and interpret, and readily connects models of lenses, mirrors, fibres and other optics to aid simulating complex multi-component etalon systems. To validate the etalon model, its predictions were verified using a previously validated model based on Fourier optics. To demonstrate its utility, three different etalon systems were simulated. The results suggest the model is valid and versatile and could aid in designing and understanding a range of systems containing planar FP etalons. The method could be extended to model higher order beams, other FP type devices such as plano-concave resonators, and more complex etalon systems such as those involving tilted components

Development and Validation of a PCR-ELISA for the Diagnosis of Symptomatic and Asymptomatic Infection by Leishmania (Leishmania) infantum

A kDNA PCR enzyme-linked immunosorbent assay (kDNA PCR-ELISA) for the diagnosis of human visceral leishmaniasis (HVL) was developed. The detection limit of the reaction, precision measurements, and cut-off of the kDNA PCR-ELISA were defined in a proof-of-concept phase. A reference strain of Leishmania (Leishmania) infantum and a bank of 14 peripheral blood samples from immunocompetent patients with VL were characterized using techniques considered gold standards, and 11 blood samples obtained from healthy individuals of an endemic area were also assessed. Phase II evaluation determined the performance of the assay in peripheral blood samples from 105 patients with VL (adults and children), 25 patients with Leishmania/HIV coinfection, 40 healthy individuals, and 33 asymptomatic individuals living in endemic areas. The kDNA PCR-ELISA exhibited satisfactory precision, with a detection limit of 0.07 fg of DNA from L. (L.) infantum and 1 parasite/mL blood. The overall sensitivity of the assay for all groups studied was 100% (95% confidence interval [CI]: 97.1–100%), and the specificity was 95% (95% CI: 83.5–98.6%). The kDNA PCR-ELISA was shown to be a useful tool for VL symptomatic and asymptomatic individuals diagnosis and its use in endemic countries may help monitor control interventions

Host determinants of infectiousness in smear-positive patients with pulmonary tuberculosis

Background Epidemiologic data suggests that only a minority of tuberculosis (TB) patients are infectious. Cough aerosol sampling is a novel quantitative method to measure TB infectiousness. Methods We analyzed data from three studies conducted in Uganda and Brazil over a 13-year period. We included sputum acid fast bacilli (AFB) and culture positive pulmonary TB patients and used a cough aerosol sampling system (CASS) to measure the number of colony-forming units (CFU) of Mycobacterium tuberculosis in cough-generated aerosols as a measure for infectiousness. Aerosol data was categorized as: aerosol negative (CFU = 0) and aerosol positive (CFU > 0). Logistic regression models were built to identify factors associated with aerosol positivity. Results M. tuberculosis was isolated by culture from cough aerosols in 100/233 (43%) TB patients. In an unadjusted analysis, aerosol positivity was associated with fewer days of antituberculous therapy before CASS sampling (p = .0001), higher sputum AFB smear grade (p = .01), shorter days to positivity in liquid culture media (p = .02), and larger sputum volume (p = .03). In an adjusted analysis, only fewer days of TB treatment (OR 1.47 per 1 day of therapy, 95% CI 1.16-1.89; p = .001) was associated with aerosol positivity. Conclusion Cough generated aerosols containing viable M. tuberculosis, the infectious moiety in TB, are detected in a minority of TB patients and rapidly become non-culturable after initiation of antituberculous treatment. Mechanistic studies are needed to further elucidate these findings.publishersversionpublishe

Mycobacterium tuberculosis progresses through two phases of latent infection in humans

Little is known about the physiology of latent Mycobacterium tuberculosis infection. We studied the mutational rates of 24 index tuberculosis (TB) cases and their latently infected household contacts who developed active TB up to 5.25 years later, as an indication of bacterial physiological state and possible generation times during latent TB infection in humans. Here we report that the rate of new mutations in the M. tuberculosis genome decline dramatically after two years of latent infection (two-sided p < 0.001, assuming an 18 h generation time equal to log phase M. tuberculosis, with latency period modeled as a continuous variable). Alternatively, assuming a fixed mutation rate, the generation time increases over the latency duration. Mutations indicative of oxidative stress do not increase with increasing latency duration suggesting a lack of host or bacterial derived mutational stress. These results suggest that M. tuberculosis enters a quiescent state during latency, decreasing the risk for mutational drug resistance and increasing generation time, but potentially increasing bacterial tolerance to drugs that target actively growing bacteria.publishersversionpublishe