Novel antifungal drugs are urgently needed to treat candidiasis caused by the emerging fungal multidrug-resistant pathogen Candida auris. In this study, the most cost-effective drug repurposing ...technology was adopted to identify an appropriate option among the 1615 clinically approved drugs with anti-C. auris activity. High-throughput virtual screening of 1,3-beta-glucanosyltransferase inhibitors was conducted, followed by an analysis of the stability of 1,3-beta-glucanosyltransferase drug complexes and 1,3-beta-glucanosyltransferase–dutasteride metabolite interactions and the confirmation of their activity in biofilm formation and planktonic growth. The analysis identified dutasteride, a drug with no prior antifungal indications, as a potential medication for anti-auris activity in seven clinical C. auris isolates from Saudi Arabian patients. Dutasteride was effective at inhibiting biofilm formation by C. auris while also causing a significant reduction in planktonic growth. Dutasteride treatment resulted in disruption of the cell membrane, the lysis of cells, and crushed surfaces on C. auris, and significant (p-value = 0.0057) shrinkage in the length of C. auris was noted at 100,000×. In conclusion, the use of repurposed dutasteride with anti-C. auris potential can enable rapid recovery in patients with difficult-to-treat candidiasis caused by C. auris and reduce the transmission of nosocomial infection.
Entomopathogenic fungi play an important role in the biological control of the insect pest population in an agroecosystem. Metarhizium anisopliae is one such entomopathogenic fungus, proved to be an ...effective biocontrol agent against different insect pests. However, different strains of entomopathogens show variations in their pathogenicity and host specificity. Hence the present study is aimed to determine the bioefficacy of local isolates of the entomopathogenic fungus M. anisopliae to control Dysdercus cingulatus. Fungal strains were isolated from cotton fields in Tirunelveli, Thoothukudi, Thenkasi, and Viruthunagar districts of Tamil Nadu following standard protocols. Four different isolates were identified and used for the bioassay. Bioefficacy trials were carried out in all the five nymphal instars and the adults of D. cingulatus and were treated with eight different concentrations of M. anisopliae (101,102,103,104,105,106,107and 108 spores/mL). The formulations were evaluated for their pathogenicity and efficiency against D. cingulatusnymphal instars and adults which resulted in 70% to 100% mortality. A 100% mortality rate was observed in four isolates of M. anisopliae at higher concentrations (120 hrs) after treatment. Lethal concentration (LC50) values of M. anisopliae isolates against D. cingulatus were calculated as 5.94×107(ERUM1), 6.09×107(ERUM2), 2.62×107(ERUM3), 2.69×107(ERUM4). Approaching biocontrol agents instead of chemical pesticides seems to be very promising in the march towards more sustainable, eco-friendly agricultural pest management practices and protecting the environment
Entomopathogenic fungi (EPF) are the microorganisms thatspecifically infect and often kill insects and other arthropods. EPF is themost effective biocontrol agent against insects in the natural ...ecosystem whichcould be an effective alternative to chemical insecticides in bio-intensivepest management. Beauveria bassiana, one of the most prevalentsoil-borne entomopathogens, has virulence on insect pests. The present study isaimed to evaluate the pathogenicity of a native isolate of the entomopathogenicfungus B. bassiana isolated from the soil samples of a cotton field(Kuthukkal) in the Tirunelveli district of Tamil Nadu against Dysdercuscingulatus. Bio-efficacy trials were carried out with six differentconcentrations viz., 4.6 × 103,1.5× 104, 5.0 × 105, 2.7 × 106, 3.2 × 107,and 2.8 x 108 (spores/mL) in all the five nymphal instars and theadults of D. cingulatus. A 100% mortality was observed in higherconcentrations 2.8 x 108 (spores/mL) at 120hrs after treatment. The resultsof the present study show that the isolate seems to be highly promising in thepest management of D. cingulatus.
Assassin bugs are terrestrial predators belonging to the family Reduviidae. Among the 24 subfamilies, harparctorinae is predominant and extensively investigated for biocontrol applications compared ...to the others subfamilies in Reduviidae. Being natural enemies of phytophagous insects, understanding the phylogeny of these predatory bugs can precise the selection of candidates to employ in insect pest management. In addition to morphological systematics, complete mitochondrial genome sequences provide great insights into the phylogeny for resolving evolutionary complexity. Complete mitochondrial genomes of four potential predatory harpactorinae and one outgroup triatominae were retrieved from NCBI GenBank database. Comparative analysis of the five mitogenomes and the nucleotide sequence between nad1 and nad2 genes were selected as the best option to distinguish. The nucleotide sequence between nad1- nad2 are found to be biased towards A and T similar to their respective complete mitogenomes. Tajima’s test of neutrality suggest that the evolutionary selection at nad1-nad2 was parallel to the complete mitogenome and showed positive and significant (p > 0.1) with high nucleotide diversity. Unequal evolutionary rate at nad1-nad2 between lineages observed in Tajima’s relative rate test and proved the nucleotide sequences of nad1-nad2 between species are highly variable. Comparing the phylogenetic trees generated using the complete mitogenomes and nad1-nad2 genes uncovered the correlation between the trees and having identical branches with varying bootstrap values. Conventionally the highly conserved protein-coding cox1 gene is used for molecular taxonomy whereas this study provides an additional and/or a possible alternative molecular marker for genetic comparative test (the nucleotide sequence between nad1-nad2) to understand the systematics and phylogeny of Reduviidae. The significant nucleotide diversity, high genetic distance and less genetic similarity of the sequence between nad1-nad2 genes among the species studied, Agriosphodrus dohrni, Rhynocoris fuscipes, Scipinia horrida, and Velinus nodipes undoubtedly propose the possible utilization of nad1-nad2 region as distinguishable molecular marker.
Lepidopteran insect pests voraciously feed the vegetable crops and causes yield loss every year. Chemical insecticides widely used to control the destructive pest incidence which heavily affects the ...beneficial and non-target organisms and in the mean time, pests developed resistance. Biopesticides are being developed to minimize these ill effects. Plants synthesize secondary metabolites to prevent from biotic and abiotic stresses. More than 27 families of pteridophyta (ferns) are reported with phytoecdysteroids (PEs). PEs are analogues of insect moulting hormone and acts as insect growth regulators (IGRs). The present study aimed to isolate the phytoecdysteroid fraction from the fern, Pityrogramma calomelanos, preliminary screening of phytochemicals using standard protocols including UV-Visible spectrophotometric analysis and survival, growth and developmental periods of Spodoptera litura treated with phytoecdysteroid fraction. Steroids and phenolic compounds were present in the fraction and six prominent peaks were recorded between the wavelength of 200-800nm. Spodoptera litura larvae treated with phytoecdysteroid fraction showed maximum larval mortality (68%) in 2000ppm (LC50 = 1473ppm; F = 48.65; p = 0.049). Pupation, pupal weight and adult emergence were decreased in higher concentrations. Pupal mortality was relatively high in treated group than control (2.04%). Larvae treated with minimal concentrations exhibited developmental deformities includes larval - pupal, pupal -adult intermediates, deformed pupae, ecdysial failure, adultoids, early/late developmental periods and it may due to the interaction of phytoecdysteroid fraction to the insect endocrine system. Therefore, phytoecdysteroid mediated biopesticide formulation could be the better alternative to commercial chemical insecticides under IPM programme.
The polyphagous, ubiquitous, destructive pest, Spodoptera litura(F.) affects 150 host plant species and notably their larval forms arenotorious. Extensive feeding and rapid reproduction cycles led ...the farmers andindustrialists to seek the effective chemical and synthetic pesticides. Randomand inappropriate usages of pesticides imposed a negative impact on non-targetorganisms, environment and abiotic factors and also pest resurgence to theparticular pesticides. To overcome this unnatural incidence, biopesticides arepracticed as an alternative source. Plant botanicals play a huge role as insectgrowth regulators (IGRs) by inhibiting the regular moulting cycle, developmentand survival of insect pests. Also, the silverback fern, Pityrogramma calomelanosare reported with several secondary metabolites which are known for theirpesticidal properties. Hence, the present work was framed to study the dietaryresponses as well as nutritional indices of S. litura treated with crudeextract of P. calomelanos. The treated larvae showed dietary andpost ingestion responses prior to moulting and death. On the 4th day oftreatment, reduction in food intake (522.89 mg), larval weight gain (41.02 mg),ECI (56.25 %), ECD (46.30 %), AD (47.21 %) and RGR (3.06 mg/mg/day) wasobserved as dose dependent manner except the feacal production (378.18 mg) ascompared to control. Therefore, the ethanolic extract of a fern, P. calomelanoscan be recommended as a biopesticides for its post ingestion andanti-nutritional effects on S. litura larvae.
The crystal structure of ligand-free
E. coli glutaminyl-tRNA synthetase (GlnRS) at 2.4 Å resolution shows that substrate binding is essential to construction of a catalytically proficient active ...site. tRNA binding generates structural changes throughout the enzyme, repositioning key active site peptides that bind glutamine and ATP. The structure gives insight into longstanding questions regarding the tRNA dependence of glutaminyl adenylate formation, the coupling of amino acid and tRNA selectivities, and the roles of specific pathways for transmission of tRNA binding signals to the active site. Comparative analysis of the unliganded and tRNA-bound structures shows, in detail, how flexibility is built into the enzyme architecture and suggests that the induced-fit transitions are a key underlying determinant of both amino acid and tRNA specificity.
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