Insecticide Resistance Mechanisms in the Green Peach Aphid Myzus persicae (Hemiptera: Aphididae) II: Costs and Benefits

feeds upon a huge diversity of hosts, it has been exposed to a wide variety of plant allelochemicals, which probably have promoted a wide range of detoxification systems. on both hosts, but they increased the transcriptional levels of two genes. than susceptible genotypes on radish, the more unfavorable host. Susceptible genotypes should be able to tolerate the defended host by up-regulating some metabolic genes that are also responding to insecticides. Hence, our results suggest that the trade-off among resistance mechanisms might be quite complex, with a multiplicity of costs and benefits depending on the environment

Nanoparticles from evaporite materials in Colombian coal mine drainages

Ultrathin and nanometric materials (minerals and amorphous phases) are detected in transitory deposits of potential hazardous elements (PHEs), especially in acidic coal mine drainages. The main goal of this work was to evaluate the occurrence of PHEs in nanoparticles (NPs) in evaporative structures in coal mining areas with high concentrations of PHEs. The precipitates were sampled in several coal mining areas in Colombia, with the purpose of evaluating the geochemical and environmental structures. In the present work, to better diagnose areas affected by coal mining, an innovative analytical procedure is proposed to define the association between PHEs in mine drainage sediments. The procedure includes the analytical study with X-Ray Diffraction (XRD) and advanced electron microscopy, before and after a series of sequential extractions to separate amorphous, magnetic, and crystalline compounds. Of the three main types of precipitates identified, the yellowish precipitates had the highest amounts of PHEs while the white precipitates had only small amounts of PHEs and the greenish precipitates contained TiO2 nanoparticles. The results from this study will be usable for more than fifty countries that have coal mine drainages

Sex Differences in Desiccation Tolerance Varies by Colony in the Mesic Liverwort \u3ci\u3ePlagiochila porelloides\u3c/i\u3e

Water scarcity, a common stress factor, negatively impacts plant performance. Strategies to cope with it, such as desiccation tolerance, are becoming increasingly important to investigate. However, phenomena, such as intraspecific variation in stress responses have not received much attention. Knowledge of this variability and the environmental drivers can be leveraged to further investigate the mechanisms of desiccation tolerance. Here we tested for variation in desiccation tolerance in Plagiochila porelloides among colonies and sexes within the same riparian zone. Field-collected dehardened plants were subjected to a desiccation event, under controlled conditions and then rehydrated. Plant water status, photosynthetic rates, net carbon gain, and efficiency of photosystem II (PSII) were assayed to evaluate tissue desiccation, basic metabolic processes and plant recovery. To establish a linkage between plant response and environmental factors, field light conditions were measured. We detected intraspecific variation, where a more exposed colony (high percentage of open sky, large temporal range of light quantity, and high red/far-red ratio) showed sex differences in desiccation tolerance and recovery. Overall, PSII recovery occurred by 72 h after rehydration, with a positive carbon gain occurring by day 30. This within species variation suggests plastic or genetic effects, and likely association with light conditions

Increasing Accessibility to Birth Control: Over the Counter Oral Birth Control

The increasing barriers to the accessibility of birth control have prompted a need for a solution. One long standing solution suggested to diminish the barriers is by removing the prescription requirement of oral contraceptives. Removing the prescription requirement not only breaks down barriers for women without healthcare access but also allows women an opportunity to control their reproduction with more accessibility. Although this solution appears to be concise, the reality is there are many different views regarding offering birth control over the counter, including some healthcare professionals who believe the health risks outweigh the access benefit. On the contrary, those in support of removing the prescription barrier for oral contraceptives, including the American Medical Association, argue that the risks women undergo through pregnancy outweigh the risks of consuming oral contraceptives. Throughout this review article, research investigating both the advantages and disadvantages of the suggested solution is discussed assessing the potential outcomes of having oral contraceptives offered over the counter

Insecticide Resistance Mechanisms in the Green Peach Aphid Myzus persicae (Hemiptera: Aphididae) I: A Transcriptomic Survey

BACKGROUND: Insecticide resistance is one of the best examples of rapid micro-evolution found in nature. Since the development of the first synthetic insecticide in 1939, humans have invested considerable effort to stay ahead of resistance phenotypes that repeatedly develop in insects. Aphids are a group of insects that have become global pests in agriculture and frequently exhibit insecticide resistance. The green peach aphid, Myzus persicae, has developed resistance to at least seventy different synthetic compounds, and different insecticide resistance mechanisms have been reported worldwide. METHODOLOGY/PRINCIPAL FINDINGS: To further characterize this resistance, we analyzed genome-wide transcriptional responses in three genotypes of M. persicae, each exhibiting different resistance mechanisms, in response to an anti-cholinesterase insecticide. The sensitive genotype (exhibiting no resistance mechanism) responded to the insecticide by up-regulating 183 genes primarily ones related to energy metabolism, detoxifying enzymes, proteins of extracellular transport, peptidases and cuticular proteins. The second genotype (resistant through a kdr sodium channel mutation), up-regulated 17 genes coding for detoxifying enzymes, peptidase and cuticular proteins. Finally, a multiply resistant genotype (carrying kdr and a modified acetylcholinesterase), up-regulated only 7 genes, appears not to require induced insecticide detoxification, and instead down-regulated many genes. CONCLUSIONS/SIGNIFICANCE: This study suggests strongly that insecticide resistance in M. persicae is more complex that has been described, with the participation of a broad array of resistance mechanisms. The sensitive genotype exhibited the highest transcriptional plasticity, accounting for the wide range of potential adaptations to insecticides that this species can evolve. In contrast, the multiply resistant genotype exhibited a low transcriptional plasticity, even for the expression of genes encoding enzymes involved in insecticide detoxification. Our results emphasize the value of microarray studies to search for regulated genes in insects, but also highlights the many ways those different genotypes can assemble resistant phenotypes depending on the environmental pressure

Molecular determinants of improved cathepsin B inhibition by new cystatins obtained by DNA shuffling

Background: Cystatins are inhibitors of cysteine proteases. The majority are only weak inhibitors of human cathepsin B, which has been associated with cancer, Alzheimer's disease and arthritis. Results: Starting from the sequences of oryzacystatin-1 and canecystatin-1, a shuffling library was designed and a hybrid clone obtained, which presented higher inhibitory activity towards cathepsin B. This clone presented two unanticipated point mutations as well as an N-terminal deletion. Reversing each point mutation independently or both simultaneously abolishes the inhibitory activity towards cathepsin B. Homology modeling together with experimental studies of the reverse mutants revealed the likely molecular determinants of the improved inhibitory activity to be related to decreased protein stability. Conclusion: A combination of experimental approaches including gene shuffling, enzyme assays and reverse mutation allied to molecular modeling has shed light upon the unexpected inhibitory properties of certain cystatin mutants against Cathepsin B. We conclude that mutations disrupting the hydrophobic core of phytocystatins increase the flexibility of the N-terminus, leading to an increase in inhibitory activity. Such mutations need not affect the inhibitory site directly but may be observed distant from it and manifest their effects via an uncoupling of its three components as a result of increased protein flexibility.State of Sao Paulo Research Foundation (FAPESP)[1998/14138-2]State of Sao Paulo Research Foundation (FAPESP)[05/59833-5]State of Sao Paulo Research Foundation (FAPESP)[08/58316-5

Surface modification of bamboo fibers using chitosan and functionalization with AuNPs

In this work, a new surface modification of the bamboo substrate with chitosan was studied, followed by subsequent treatment with gold nanoparticles (AuNP) by the exhaustion method, aiming at obtaining a technical textile with ultraviolet (UV) protection. The treatment with chitosan in the bamboo substrate induced an increase in the AuNP adsorption due to the electrostatic interactions between the chitosan amino groups and the citrate ion that surrounds the AuNP. The nanoparticles were obtained by the chemical reduction method, with some adaptations, using sodium citrate as a reducing agent/stabilizer and chlorouronic acid as precursor. The AuNP were characterized by transmission electron microscopy (TEM) and reflection, showing an average size of 35 nm. The presence of AuNP on the fiber surface was confirmed by SEM and XRD, with crystallographic peaks characteristic of gold. The UV protection factor was tested on the material, demonstrating excellent results.info:eu-repo/semantics/publishedVersio

Net-phase flow NMR for compact applications

The net phase of the NMR signal is proposed as a robust mechanism for the encoding of fluid flow velocity into phase, showing local bijectivity. While magnitude-based or imaging-based methods suffer from loss of signal, by increasing the flow rate, the present method enables us to maintain the high SNR even for the case of fast flow. In addition, it is shown that a well-engineered flow channel is also necessary, which is not the case for traditional cylindrical flow channels. In this contribution, we report on implementing this approach in a low-cost NMR-based flowmeter for use in a low field (1 T) setting, for example, for monitoring reaction flow industrial processes