Non-steroidal ecdysteroid agonist chromafenozide: Gene induction activity, cell proliferation inhibition and larvicidal activity

The activity profile of the most recent commercial non-steroidal ecdysteroid agonist chromafenozide (ANS-118), was evaluated on a comparative basis to methoxyfenozide (RH-2485) that is to date the most potent commercial agonist against Lepidoptera. This was done first at the molecular and cellular level regarding its induction activity of an ecdysteroid-responsive reporter gene and its cell proliferation inhibition activity, and subsequently at the level of larvicidal toxicity. For in vitro experiments three ecdysteroid-responsive insect cell lines were used: Drosophila melanogaster (Diptera) S2 cells, Bombyx mori (Lepidoptera) Bm5 cells and Spodoptera exigua (Lepidoptera) Se4 cells. The in vivo toxicity was scored against two major lepidopteran pests in the world, the beet armyworm S. exigua and the cotton leafworm Spodoptera littoralis. In vitro results revealed that chromafenozide and methoxyfenozide are highly potent against lepidopteran cells compared to dipteran cells, supporting the lepidopteran-specificity of these compounds. Interestingly, in the reporter gene induction experiments and proliferation inhibition experiments, a slightly higher efficacy was observed in S2 compared to Bm5 cells at high concentrations of chromafenozide and methoxyfenozide. Our analysis shows the high potency and efficacy of the chromafenozide compound as an ecdysteroid agonist towards lepidopteran insects at a level that is similar to methoxyfenozide.     

Biochemical mechanisms of methoxyfenozide resistance in the cotton leafworm Spodoptera littoralis

BACKGROUND: Methoxyfenozide is a lepidopteran‐specific insecticide that belongs to a new group of insecticides, the non‐steroidal ecdysteroid agonists, also called moulting accelerating compounds (MACs). To investigate the risk of resistance and possible mechanisms conferring resistance to methoxyfenozide, the authors selected in the laboratory for a resistant strain of the cotton leafworm Spodoptera littoralis (Boisd.), which is a representative lepidopteran model and an important pest in cotton and vegetables worldwide, with a high risk for resistance development. RESULTS: After selection with methoxyfenozide during 13 generations, toxicity data showed that the selected strain developed fivefold resistance to methoxyfenozide in comparison with the susceptible strain. Measurement of the detoxification enzymes demonstrated that the monooxygenase (MO) activity was 2.1 times higher in the selected strain, whereas there was no change for esterases and glutathione‐S‐transferases. When the inhibitors piperonyl butoxide (PBO), S,S,S‐tributyl phosphorotrithioate (DEF) and diethyl maleate were tested as synergists, the respective synergistic ratios were 0.97, 0.96 and 1.0 for the susceptible strain, and 2.2, 0.96 and 1.1 for the resistant strain. The significant synergistic effect by PBO concurs with the increased MO activity in the selected strain. CONCLUSION: Taken overall, the present study supports the importance of MO‐mediated metabolism in resistance to methoxyfenozide, directing tactics to fight against resistance development for this novel group of insecticides. Copyright © 2009 Society of Chemical Industry     

Foliar Application of Iron (Fe) Improved the Antioxidant Defense and Cd Accumulation Potential of <Emphasis Type="Italic">Ricinus communis</Emphasis> Under Hydroponic Condition

Heavy metal-polluted water has become a problem for sustainable environment, agriculture, and human health. Phyto-accumulation is an eco-friendly technique for decontamination of metal-polluted water and soil. The efficiency of phyto-accumulation and rhizo-filtration can be enhanced by the application of certain nutrients to accumulator plants. In this study, we focused on the role of iron (Fe) in rhizo-filtration and phyto-accumulation of cadmium (Cd) from polluted water/media, using Ricinus communis plant. Medium was contaminated with 10 ppm Cd while Fe (2.50, 5.00, and 7.50 ppm) was applied both as foliar spray and medium addition separately. Accumulation of Cd and concentrations of soluble proline, phenolic compounds, and chlorophylls were measured in plant tissues. Addition of Fe into media significantly increased biomass in the plants but decreased Cd absorption by roots and its accumulation in other tissues of the plants. Foliar application of Fe, especially 7.5 ppm, significantly increased biomass as well as accumulation of Cd in tissues of the plants. Contents of soluble proline (41.88?±?3.56 ppm) and phenolics (171.00?±?4.98 ppm) in leaves were highly increased by foliar spray of 7.5 ppm Fe on the plants. On the other hand, highest concentrations of free proline (67.00?±?2.00 ppm) and total phenolics (82.67?±?2.52 ppm) in plant roots were observed in 7.5 ppm Fe added to media and as foliar spray, respectively. Strong correlations were observed between phenolics content in roots and leaves with Cd accumulation after foliar application of 7.5 ppm Fe.     

Influence of nano-iron oxide and zinc sulfate on physiological characteristics of peppermint

To evaluate the impact of nano-iron oxide and zinc sulfate fertilizers on peppermint in field conditions, a factorial split experiment with two micro-nutrient fertilizers [Zinc (Zn) and Iron (Fe)] in RCBD with three replicates was conducted at University of Tehran, during 2014 and 2015. Fe at four levels (0, 0.25, 0.5, and 0.75 g L-1) and Zn at three levels (0, 2.5, and 5 g L-1) were applied. Fe and Zn fertilizer application significantly improved photosynthetic pigments, mineral nutrient content, essential oil concentration, and dry matter yield in peppermint. The highest iron content (1578.00 mg kg^?1) was achieved when 5 g L^?1 of Zn was applied along with 0.75 g L^?1 Fe. According to our results, the application of 2.5 g L^?1 of Zn plus 0.5 g L^?1 Fe fertilizers could be recommended to achieve the highest plant dry matter and essential oil yield.     

Assessment of species specificity of moulting accelerating compounds in Lepidoptera: comparison of activity between Bombyx mori and Spodoptera littoralis by in vitro reporter and in vivo toxicity assays

BACKGROUND: Dibenzoylhydrazine analogues have been developed successfully as a new group of insect growth regulators, called ecdysone agonists or moulting accelerating compounds. A notable feature is their high activity against lepidopteran insects, raising the question as to whether species‐specific analogues can be isolated. In this study, the specificity of ecdysone agonists was addressed through a comparative analysis in two important lepidopterans, the silkworm Bombyx mori L. and the cotton leafworm Spodoptera littoralis (Boisd.). RESULTS: When collections of non‐steroidal ecdysone agonists containing different mother structures (dibenzoylhydrazine, acylaminoketone, tetrahydroquinoline) were tested, in vitro reporter assays showed minor differences using cell lines derived from both species. However, when compounds with high ecdysone agonist activity were examined in toxicity assays, larvicidal activity differed considerably. Of note was the identification of three dibenzoylhydrazine analogues with > 100‐fold higher activity against Bombyx than against Spodoptera larvae. CONCLUSION: The present study demonstrated that species‐specific ecdysone‐agonist‐based insecticides can be developed, but their species specificity is not based on differences in the activation of the ecdysone receptor but rather on unidentified in vivo parameters such as permeability of the cuticle, uptake/excretion by the gut or metabolic detoxification. Copyright © 2010 Society of Chemical Industry     

Grain filling pattern of Hordeum vulgare as affected by salicylic acid and salt stress

Although application of salicylic acid (SA) to various plants grown on saline soils has been examined adequately, the effect of SA on changes during grain filling period has not been studied in details. In this 2-year field study, the grain-filling pattern of barley has been monitored as affected by different SA concentrations (0, 0.5, 1.0, 1.5, and 2.0?mM) under varied irrigation salinity levels (2 and 12?dSm^?1) during 2012–2013 and 2013–2014 growing seasons. In both years, total soluble carbohydrates (TSC) increased up to 15?days after anthesis (DAA) and then decreased until the end of the grain-filling period. However, starch content (SC) and the mean grain weight (MGW) increased form the first sampling, and such increase was substantial between 15 and 25 DAA. The grain growth rate (GGR) and the absolute grain growth rate (AGGR) were enhanced up to 20 DAA and then were reduced until 30 DAA. The grain-filling pattern changed by salt stress, so that TSC was greater for the salt stressed plants from 15 or 10 DAA in the first and the second years, respectively. Throughout the grain-filling period, SC, MGW, and AGGR were lower under saline conditions in both years. Application of SA increased TSC, SC, MGW, GGR, and AGGR from 15 to 20 DAA, however, the effect of SA was obvious earlier under saline than the non-saline conditions. Generally, it can be concluded that SA foliar application might increase grain weight through modulating the negative impact of salt stress on carbohydrate and starch contents. It also appeared that the effect of SA was obvious earlier under salt stress conditions.     

Fabrication and Characterization of Nanocomposite Hydrogel Based on Alginate/Nano-Hydroxyapatite Loaded with Linum usitatissimum Extract as a Bone Tissue Engineering Scaffold

In the current paper, we fabricated, characterized, and applied nanocomposite hydrogel based on alginate (Alg) and nano-hydroxyapatite (nHA) loaded with phenolic purified extracts from the aerial part of Linum usitatissimum (LOH) as the bone tissue engineering scaffold. nHA was synthesized based on the wet chemical technique/precipitation reaction and incorporated into Alg hydrogel as the filler via physical cross-linking. The characterizations (SEM, DLS, and Zeta potential) revealed that the synthesized nHA possess a plate-like shape with nanometric dimensions. The fabricated nanocomposite has a porous architecture with interconnected pores. The average pore size was in the range of 100–200 µm and the porosity range of 80–90%. The LOH release measurement showed that about 90% of the loaded drug was released within 12 h followed by a sustained release over 48 h. The in vitro assessments showed that the nanocomposite possesses significant antioxidant activity promoting bone regeneration. The hemolysis induction measurement showed that the nanocomposites were hemocompatible with negligible hemolysis induction. The cell viability/proliferation confirmed the biocompatibility of the nanocomposites, which induced proliferative effects in a dose-dependent manner. This study revealed the fabricated nanocomposites are bioactive and osteoactive applicable for bone tissue engineering applications.     

The method of application and short term results of tympanostomy tubes for the treatment of primary secretory otitis media in three Cavalier King Charles Spaniel dogs

Primary secretory otitis media is an uncommon disease affecting predominantly Cavalier King Charles Spaniel dogs. Current treatment recommendations include repeated manual removal of the mucoid effusion from the tympanic cavity through a myringotomy incision and topical or systemic corticosteroids. The aim of this study was to assess the efficacy of tympanostomy tubes to provide continual tympanic cavity ventilation and drainage for the treatment of primary secretory otitis media in three dogs. Tympanostomy tubes were placed within a myringotomy incision in the pars tensa with the aid of an operating microscope. Clinical signs resolved rapidly in all cases following the procedure and all cases were asymptomatic at the time of follow-up, 8, 6 and 4 months later. Results of this study indicate that tympanostomy tubes provide continual tympanic cavity ventilation and drainage and may be an acceptable alternative to repeated myringotomy for the treatment of primary secretory otitis media.     

Evaluation of Salinity Tolerance of Some Selected Almond Genotypes Budded on GF677 Rootstock

ABSTRACT

In order to evaluate the tolerance of some almond genotypes to salinity, a factorial experiment was carried out based on completely randomized design (CRD), with two factors: genotypes in 11 levels (Tuono, Nonparaeil, Mamaie, Shokoufeh, Sahand, ‘Ferragnès,’ 1–16, 1–25, A₂₀₀, 13–40 budded on GF₆₇₇ rootstock, and GF₆₇₇ (without budding)) and irrigation water salinity in five levels (0, 1.2, 2.4, 3.6, and 4.8 g/l of natural salt (equal electrical conductivity 0.5, 2.5, 4.9, 7.3, and 9.8 dS/m, respectively) and with 4 replication for each treatment in research greenhouse of Seed and Plant Institute in years 2013 and 2014. The results showed that with increasing salinity concentration, growth indicators include the branch height, branch diameter, number of total leaves, percentage of green leaves, leaf density on the main branch, leaf area and leaf area ratio, relative humidity content, chlorophyll index, chlorophylls a, b, total, scion fresh and dry weight, root fresh and dry weight have been reduced in the all genotypes studied, but percentage of necrotic leaves, percentage of downfall leaves, root fresh and dry weight ratio to scion fresh and dry weight, relative ionic percentage, and cell membrane injury percentage of leaves were increased. The results of chlorophyll fluorescence showed that salinity stress affected on the young trees by increasing the amount of minimum fluorescence (F_O) and decreasing the maximum fluorescence (F_m) and reduced variable fluorescence (F_v) in the plants and reduced variable fluorescence ratio to maximum fluorescence of 0.83 in the control plants to 0.72 in Sahand cultivar and GF₆₇₇ rootstock. The result showed that type of scion was affected in obstruction of Na⁺ absorption by the roots and their transported to leaves, as well as was affected in increasing uptake of K⁺ by the roots and their transported to leaves. In this research, GF₆₇₇ is well tolerated to water salinity to 4.9 dS/m but with higher range of salinity showed stress effects. The result showed that type of genotypes budded on GF₆₇₇ rootstock was very effective in tolerant to salinity. Overall, ‘Ferragnès’ was recognized as the most tolerant cultivar to salinity stress. This cultivar could tolerate salinity 3.6 g/l (Ec: 7.3 dS/m). Also, Sahand was recognized as the most sensitive cultivar to salinity stress.