The Potential of Metarhizium anisopliae Blastospores to Control Aedes aegypti Larvae in the Field

Entomopathogenic fungi are promising as an environmentally benign alternative to chemical pesticides for mosquito control. The current study investigated the virulence of Metarhizium anisopliae blastospores against Aedes aegypti under both laboratory and field conditions. Virulence bioassays of conidia and blastospores were conducted in the laboratory, while field simulation bioassays were conducted under two conditions: totally shaded (TS) or partially shaded (PS). In the first bioassay (zero h), the larvae were added to the cups shortly after the preparation of the blastospores, and in the subsequent assays, larvae were added to the cups 3, 6, 9, and 12 days later. The survival of the larvae exposed to blastospores in the laboratory was zero on day two, as was the case for the larvae exposed to conidia on the sixth day. Under TS conditions, zero survival was seen on the third day of the bioassay. Under PS conditions, low survival rates were recorded on day 7. For the persistence bioassay under PS conditions, low survival rates were also observed. Metarhizium anisopliae blastospores were more virulent to Ae. aegypti larvae than conidia in the laboratory. Blastospores remained virulent under field simulation conditions. However, virulence rapidly declined from the third day of field bioassays. Formulating blastospores in vegetable oil could protect these propagules when applied under adverse conditions. This is the first time that blastospores have been tested against mosquito larvae under simulated field conditions, and the current study could be the basis for the development of a new biological control agent

Telomere length de novo assembly of all 7 chromosomes and mitogenome sequencing of the model entomopathogenic fungus, Metarhizium brunneum, by means of a novel assembly pipeline

BackgroundMore accurate and complete reference genomes have improved understanding of gene function, biology, and evolutionary mechanisms. Hybrid genome assembly approaches leverage benefits of both long, relatively error-prone reads from third-generation sequencing technologies and short, accurate reads from second-generation sequencing technologies, to produce more accurate and contiguous de novo genome assemblies in comparison to using either technology independently. In this study, we present a novel hybrid assembly pipeline that allowed for both mitogenome de novo assembly and telomere length de novo assembly of all 7 chromosomes of the model entomopathogenic fungus, Metarhizium brunneum.ResultsThe improved assembly allowed for better ab initio gene prediction and a more BUSCO complete proteome set has been generated in comparison to the eight current NCBI reference Metarhizium spp. genomes. Remarkably, we note that including the mitogenome in ab initio gene prediction training improved overall gene prediction. The assembly was further validated by comparing contig assembly agreement across various assemblers, assessing the assembly performance of each tool. Genomic synteny and orthologous protein clusters were compared between Metarhizium brunneum and three other Hypocreales species with complete genomes, identifying core proteins, and listing orthologous protein clusters shared uniquely between the two entomopathogenic fungal species, so as to further facilitate the understanding of molecular mechanisms underpinning fungal-insect pathogenesis.ConclusionsThe novel assembly pipeline may be used for other haploid fungal species, facilitating the need to produce high-quality reference fungal genomes, leading to better understanding of fungal genomic evolution, chromosome structuring and gene regulation

Evaluation of Fungal Volatile Organic Compounds for Control the Plant Parasitic Nematode Meloidogyne incognita

Plant parasitic nematodes are a serious threat to crop production worldwide and their control is extremely challenging. Fungal volatile organic compounds (VOCs) provide an ecofriendly alternative to synthetic nematicides, many of which have been withdrawn due to the risks they pose to humans and the environment. This study investigated the biocidal properties of two fungal VOCs, 1-Octen-3-ol and 3-Octanone, against the widespread root-knot nematode Meloidogyne incognita. Both VOCs proved to be highly toxic to the infective second-stage juveniles (J2) and inhibited hatching. Toxicity was dependent on the dose and period of exposure. The LD50 of 1-Octen-3-ol and 3-Octanone was 3.2 and 4.6 µL, respectively. The LT50 of 1-Octen-3-ol and 3-Octanone was 71.2 and 147.1 min, respectively. Both VOCs were highly toxic but 1-Octen-3-ol was more effective than 3-Octanone. Exposure of M. incognita egg-masses for 48 h at two doses (0.8 and 3.2 µL) of these VOCs showed that 1-Octen-3-ol had significantly greater nematicidal activity (100%) than 3-Octanone (14.7%) and the nematicide metham sodium (6.1%). High levels of reactive oxygen species detected in J2 exposed to 1-Octen-3-ol and 3-Octanone suggest oxidative stress was one factor contributing to mortality and needs to be investigated further

Strongly coupled fermions on the lattice

Since its inception with the pioneering work of Ken Wilson, lattice field theory has come a long way. Lattice formulations have enabled us to probe the non-perturbative structure of theories such as QCD and have also helped in exploring the phase structure and classification of phase transitions in a variety of other strongly coupled theories of interest to both high energy and condensed matter theorists. The lattice approach to QCD has led to an understanding of quark confinement, chiral symmetry breaking and hadronic physics. Correlation functions of hadronic operators and scattering matrix of hadronic states can be calculated in terms of fundamental quark and gluon degrees of freedom. Since lattice QCD is the only well-understood method for studying the low-energy regime of QCD, it can provide a solid foundation for the understanding of nucleonic structure and interaction directly from QCD. Despite these successes problems remain. In particular, the study of chiral gauge theories on the lattice is an outstanding problem of great importance owing to its theoretical implications and for its relevance to the electroweak sector of the Standard Model. However the construction of these theories is plagued by the emergence of massless chiral modes in the lattice theory which have no counterpart in the continuum theory. This is a topological obstruction known as the Nielsen-Nimonoya theorem and can be proven to hold under assumptions of translation invariance, chiral invariance and hermiticity of the lattice Hamiltonian. One strategy that was advocated by Eichten and Preskill (EP) early on in the field was to generate large masses for these additional chiral states by coupling them to additional composite fermions. These composite fermions would arise as bound states via an auxiliary Yukawa interaction. Hence in the continuum limit mirror modes will be forced to decouple from the spectrum without breaking chiral symmetry. This proposal led to many numerical studies of different models. Golterman et.al critiqued this proposal by showing that in specific realizations of the EP model the required phase containing a four fermion condensate was separated from the massless phase needed for a chiral theory by an intermediate phase in which the gauge symmetry was spontaneously broken. This was proven in the large N limit where the model contains N flavors of fermion. It led to the idea that the four-fermion phase was a lattice artifact and further work on these models stopped. However in recent few years this picture has changed. In three dimensions several studies of an SU(4) invariant four-fermion model have provided evidence in favor of a direct transition between massless(PMW) phase and four-fermion(PMS) phase. The generation of a mass without breaking symmetries via a symmetric four fermion condensate has received a lot of interest within the condensed matter community. Indeed this mechanism has been employed to gap out edge modes of topological insulators without breaking any symmetries. Of course the question for high energy physics is whether these new four fermion models exhibit this same structure in four dimensions and, if so, can it be used in the context of the original EP proposal to create a lattice theory whose low energy excitations are chiral. In this thesis I discuss the progress towards this goal

Stress-Mediated Responses of Aedes aegypti (Diptera: Culicidae) Larvae When Exposed to Metarhizium brunneum (Hypocreales: Clavicipitaceae) and Toxorhynchites brevipalpis (Diptera: Culicidae)

Aedes aegypti mosquitoes are capable of vectoring a wide range of diseases including dengue, yellow fever, and Zika viruses, with approximately half of the worlds’ population at risk from such diseases. Development of combined predator–parasite treatments for the control of larvae consistently demonstrates increased efficacy over single-agent treatments, however, the mechanism behind the interaction remains unknown. Treatments using the natural predator Toxorhynchites brevipalpis and the entomopathogenic fungus Metarhizium brunneum were applied in the laboratory against Ae. aegypti larvae as both individual and combined treatments to determine the levels of interaction between control strategies. Parallel experiments involved the removal of larvae from test arenas at set intervals during the course of the trial to record whole body caspase and phenoloxidase activities. This was measured via luminometric assay to measure larval stress factors underlying the interactions. Combined Metarhizium and Toxorhynchites treatments were seen to drastically reduce lethal times as compared to individual treatments. This was accompanied by increased phenoloxidase and caspase activities in combination treatments after 18 h (p < 0.001). The sharp increases in caspase and phenoloxidase activities suggest that combined treatments act to increase stress factor responses in the larvae that result in rapid mortality above that of either control agent individually. This work concludes that the underlying mechanism for increased lethality in combined parasite–predator treatments may be related to additive stress factors induced within the target host larvae

Optimizing the Application Timing and Dosage of<i>Metarhizium brunneum</i>(Hypocreales: Clavicipitaceae) as a Biological Control Agent of<i>Aedes aegypti</i>(Diptera: Culicidae) Larvae

Aedes aegypti (Diptera: Culicidae) is the principal vector of dengue and other viruses that cause disease among 100 to 400 million people each year. The recent development of widespread insecticidal resistance has led to the rapid development of biological control solutions aimed at larval control. While the efficacy of Metarhizium brunneum has been shown against Aedes larvae, the impact of larval population dynamics will need to be determined to formulate effective control strategies. In this study, larvae were subjected to four concentrations of M. brunneum (105, 106, 107, 108 conidia ml-1). Larvae were found to be susceptible to M. brunneum with dose-dependent efficacy. When constant larval immigration was added as a parameter, peak mortality was consistently found to occur on the fourth day, before a significant reduction in control efficacy linked to a decline in conidial availability within the water column. This suggests that M. brunneum treatments should be applied at a concentration 1 × 107 conidia ml-1 every four days to effectively control mosquito larvae in the field, regardless of the fungal formulation, water volume, or larval density. Understanding fungal-mosquito dynamics is critical in developing appropriate control programs as it helps optimize the fungal control agent's dose and frequency of application

The Impact of Compensation and Training on Organizational Performance: The Mediating Role of Employee Performance During Covid

Purpose: This study aims to measure the impact of compensation and training on organization performance along with the mediating role of employee performance during Pandemic COVID-19. Methodology: This study was done by a simple survey-based questionnaire drafted through Google Forms, and throughout the entire research, a quantitative approach has been incorporated. whereas, for the data collection, two methods, namely primary and secondary, were used, among which the questionnaire filled out was a primary method. Furthermore, this quantitative research was conducted with a population of 231 people and a sample of 149 respondents with a non-convenience sampling method adopted to gather data from respondents. Findings: After statistical tests for hypothesis testing, the study found that two hypotheses H2–the considerable impact of training on organizational performance and H4 – the significant impact of salary on employee performance were accepted. Conclusion: The compensation provided to employees, either financial or non-financial, plays a key role in retaining employees’ confidence, reducing their turnover, and motivating them to work hard, which ultimately benefits the firm. Training, on the other hand, is a crucial step towards the development, betterment, and growth of the organization as a well-trained and up-to-date workforce guarantees a successful organization. Thus, it is concluded that employee training and compensation play an important role in the growth of employees and the organization

Development and laboratory validation of a plant-derived repellent blend, effective against Aedes aegypti [Diptera: Culicidae], Anopheles gambiae [Diptera: Culicidae] and Culex quinquefasciatus [Diptera: Culicidae]

Mosquitoes of the genera Aedes, Anopheles and Culex vector a wide range of pathogens seriously affecting humans and livestock on a global scale. Over-reliance on insecticides and repellents has driven research into alternative, naturally-derived compounds to fulfil the same objectives. Steam distilled extracts of four plants with strong, yet attractive, volatile profiles were initially assessed for repellency in a dual-port olfactometer using Aedes aegypti as the model species. Picea sitchensis was found to be the most repellent, proving comparable to leading products when applied at 100% (p = 1.000). Key components of conifer-derived volatile profiles were then screened via electroantennography before those components eliciting an electrophysiological response were assayed individually in the olfactometer; according to WHO protocol. The most promising 5 were selected for reductive analyses to produce an optimised semiochemical blend. This combination, and a further two variations of the blend, were then progressed to a multi-species analysis using the BG-test whereby bite-attempt frequency on hands was assessed under different repellent treatments; assays were compared between Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus. Efficacy was found against all three species, although it was found that Ae. aegypti was the most susceptible to the repellent, with An. gambiae being the least. Here, a novel, naturally-derived blend is presented with weak spatial repellency, as confirmed in laboratory assays. Further work will be required to assess the full extent of the potential of the products, both in terms of field application and species screening; however, the success of the products developed demonstrate that plant metabolites have great capacity for use in the repellent sector; both to improve upon known compounds and to reduce the usage of toxic products currently on the market