Sublethal effects of abamectin on the biological performance of the predatory mite, <Emphasis Type="Italic">Phytoseius plumifer</Emphasis> (Acari: Phytoseiidae)

Traditionally estimating pesticide effects by measuring only lethal effect may underestimate the total negative effect on beneficial arthropods and sublethal effects should be assessed to estimate the total effect of their applications. In this study, sublethal effect of the acaricide abamectin (Vermectin^® 1.8% EC, Giah, Iran) on the predatory mite Phytoseius plumifer (Canestrini &; Fanzago) (Acari: Phytoseiidae) fed on Tetranychus urticae Koch was assessed in laboratory conditions. The adult predators were exposed to the residues of the acaricide on fig leaves and the LC₅₀ value was determined based on a concentration–response analysis. The results showed that sublethal concentrations (LC₁₀, LC₂₀ and LC₃₀) of abamectin severely affected the fecundity and longevity of the treated females of P. plumifer. Furthermore, reproductive and life table parameters of the subsequent generation were affected. The results indicated that adverse effects of abamectin on population growth of P. plumifer were significant, so the results from this study can be used to develop approximate guidelines for the use of abamectin in order to minimize their impact on P. plumifer and related natural enemies.     

Resveratrol mitigates genotoxicity induced by iodine-131 in primary human lymphocytes

The purpose of this study was to investigate the radioprotective effects of resveratrol as a natural product that protects against genotoxic actions of ¹³¹I in cultured human lymphocytes. Whole-blood samples from human volunteers were treated with resveratrol at doses of 0.5, 1, 5, and 50 μg/mL for 1 h, after which the lymphocytes were incubated with ¹³¹I (100 μCi/1.5 mL) for 2 h. The lymphocyte cultures were then mitogenically stimulated to enable evaluation of the number of micronuclei in cytokinesis-blocked binucleated cells. Incubation of lymphocytes with ¹³¹I induced genotoxicity, which was reflected by an increase in micronuclei frequency. At the doses tested, resveratrol significantly reduced micronuclei frequency. Maximal protective effects occurred at a dose of 1 μg/mL, with total micronuclei values being reduced by 65 % compared to controls. In conclusion, our results indicate protective effects of resveratrol at low doses against genetic damage and adverse effects induced by ¹³¹I administration.     

Sublethal effects of fenpyroximate on life table parameters of the predatory mite <Emphasis Type="Italic">Phytoseius plumifer</Emphasis>

Knowledge of the lethal and sublethal effects of pesticides on biological control agents is necessary for successful implementation of integrated pest management programs. The sublethal effect of acaricide fenpyroximate (Ortus^®) on performance of females and their offspring of Phytoseius plumifer (Canestrini &; Fanzago), an efficient predator of Tetranychus urticae Koch, was determined under laboratory conditions. The adult predators were exposed to the residues of the acaricide on fig leaves and the LC₅₀ value was determined based on a concentration–response analysis. The results showed that sublethal concentrations of fenpyroximate significantly affected the fecundity and longevity of the treated females of P. plumifer. Reproductive and life table parameters of the subsequent generation were also affected by sublethal concentrations. It could be concluded that sublethal concentrations can significantly reduce the population growth of P. plumifer and this should be considered in integrated pest management programs.     

Use of in silico tools for classification of novel missense mutations identified in dystrophin gene in developing countries

DMD gene which is composed of 79 exons is the largest known gene located on X chromosome (Xp21). Point mutations in the dystrophin gene are responsible for 30–35% of cases with DMD/BMD. Mutation analysis of all the exons of the DMD gene is costly in developing countries, therefore, a few of the exons are selected to be analyzed routinely in clinical laboratories. In this study, direct sequencing was used for detection of point mutations in 10 exons of dystrophin gene in patients affected with DMD without detectable large rearrangements. Freely available programs were used to predict the damaging effects of the mutations. Point mutations were successfully detected in three patients. Three novel mutations, two missense mutations located on nonconservative domains and a single nucleotide deletion, were detected. Missense mutations were predicted to change splicing efficiency. Detection of point mutations by DNA analysis followed by prediction of the pathogenecity by using bioinformatic tool might be an asset to provide proper diagnosis or genetic counseling to patients and their family.     

Synthesis of imidazopyridines and purines as potent inhibitors of leukotriene A4 hydrolase

The synthesis and biological evaluation of a series of heterocyclic analogues of the previously reported LTA(4) hydrolase inhibitor 1b are described. Imidazopyridine and purine analogues are specifically highlighted with several demonstrating excellent potency in our in vitro assays, as well as good oral activity in a mouse ex vivo assay.     

Competitive interactions of Persian oak coppice trees (<Emphasis Type="Italic">Quercus brantii</Emphasis> var. <Emphasis Type="Italic">persica</Emphasis>) in a pure dry woodland revealed through point pattern analysis

Understanding intraspecific interactions among Persian oaks is essential to predict the responses of Zagros dry woodlands purely covered by these coppice trees to environmental changes (such as drought) that have direct effects on the sustainability of these woodlands. This investigation attempted to explore the scale-dependent competition among Persian oaks and highlight the impacts of competitive interactions on their biophysical properties (i.e. tree height, diameter at root collar and crown attributes) via point pattern analysis. Structurally different summary statistics were implemented to analyse the spatial pattern of Persian oaks in a pure 9-ha study plot. Nearest neighbour distribution function D(r) indicated that these coppice trees had no nearest neighbours up to the spatial scale of 2 m, and they all had a nearest neighbour at distances shorter than 12 m. Furthermore, pair correlation function g(r) showed the significant dispersion of Persian oaks up to the scale of 5 m, which may be the outcome of intraspecific competition for resources such as soil nutrients and water. As explored by mark variograms γ _m (r), Persian oaks of the same size had significant spatial correlations that illustrated the competitive (not facilitative) interactions of these coppice trees in the study plot. Mark correlation function k _mm (r) additionally revealed negative correlations of height and radial growth up to large spatial scales. Consequently, the outcome of this study highlighted the significant effects of competitive intraspecific interactions among Persian oak coppice trees on their spatial pattern and biophysical properties.     

Pyrrolidine and piperidine analogues of SC-57461A as potent,orally active inhibitors of leukotriene A(4) hydrolase

The synthesis and biological evaluation of a series of functionalized pyrrolidine- and piperidine-containing analogues of our lead LTA(4) hydrolase inhibitor, SC-57461A, is described. A number of compounds showed excellent potency in our in vitro screens and several demonstrated good oral activity in a mouse ex vivo assay. These efforts led to the identification of SC-56938 (14) as a potent, orally active inhibitor of LTA(4) hydrolase.     

Potentiation of temozolomide cytotoxicity by poly(ADP)ribose polymerase inhibitor ABT-888 requires a conversion of single-stranded DNA damages to double-stranded DNA breaks

Poly(ADP-ribose) polymerase (PARP) senses DNA breaks and facilitates DNA repair via the polyADP-ribosylation of various DNA binding and repair proteins. We explored the mechanism of potentiation of temozolomide cytotoxicity by the PARP inhibitor ABT-888. We showed that cells treated with temozolomide need to be exposed to ABT-888 for at least 17 to 24 hours to achieve maximal cytotoxicity. The extent of cytotoxicity correlates with the level of double-stranded DNA breaks as indicated by gammaH2AX levels. In synchronized cells, damaging DNA with temozolomide in the presence of ABT-888 during the S phase generated high levels of double-stranded breaks, presumably because the single-stranded DNA breaks resulting from the cleavage of the methylated nucleotides were converted into double-stranded breaks through DNA replication. As a result, treatment of temozolomide and ABT-888 during the S phase leads to higher levels of cytotoxicity. ABT-888 inhibits poly(ADP-ribose) formation in vivo and enhances tumor growth inhibition by temozolomide in multiple models. ABT-888 is well tolerated in animal models. ABT-888 is currently in clinical trials in combination with temozolomide.