Repellent and Insecticidal Activity of Naphthoquinones from the Heartwood of Tectona grandis on Incisitermes marginipennis(Latreille)

Wood is a lignocellulosic material that,because of its organic nature,is a source of nutrients for bacteria,fungi,and insects.Incisitermes marginipennis(Latreille)is an interesting dry wood-boring termite.Because it is an extremely destructive pest,difficult to control due to its cryptic lifestyle,and for its role in the biogeochemical cycle of carbon and other elements;it is a fundamental organism.The use of less toxic and eco-friendly substances is important for protecting domestic,cultural,and historical heritage made of wood or lignocellulosic materials.The aim of this study was to evaluate the biological activity of various naphthoquinones extracted from the heartwood of T.grandis on I.marginipennis.First,heartwood flour was used for Soxhlet-type extractions to isolate and characterize the heartwood compounds by thin-layer chromatography.To identify the heartwood compounds,nuclear magnetic resonance and gas chromatography coupled to a mass spectrometer were used.The information obtained was supported using the Interactive Spectroscopy software.The identified heartwood compounds were lapachol,tectoquinone,deoxylapachol,dehydro-α-lapachone,tectol and tecomaquinone-I.Using nymphal termites of I.marginipennis as a biological model,the isolated and identified molecules were under three different tests(repellent,insecticide and protective)and their biological activity was individually evaluated.The results showed that the molecules obtained have a repellent-protective effect against I.marginipennis,although not in all cases,these molecules have high percentages of mortality and decreased the weight loss of the treated material exposed to I.marginipennis.

Don´t give up on mitochondria as a target for the treatment of diabetes and its complications

In this editorial,we discuss an article by Wang et al,focusing on the role of mitochondria in peripheral insulin resistance and insulin secretion.Despite numerous in vitro and pre-clinical studies supporting the involvement of mitochondrial dysfunction and oxidative stress in the pathogenesis of diabetes and its complications,efforts to target mitochondria for glycemic control in diabetes using mitochondria-targeted antioxidants have produced inconsistent results.The intricate functionality of mitochondria is summarized to underscore the challenges it poses as a therapeutic target.While mitochondria-targeted antioxidants have demonstrated improvement in mitochondrial function and oxidative stress in pre-clinical diabetes models,the results regarding glycemic control have been mixed,and no studies have evaluated their hypoglycemic effects in diabetic patients.Nonetheless,pre-clinical trials have shown promising outcomes in ameliorating diabetes-related complications.Here,we review some reasons why mitochondria-targeted antioxidants may not function effectively in the context of mitochondrial dysfunction.We also highlight several alternative approaches under development that may enhance the targeting of mitochondria for diabetes treatment.

Antifungal Activity of Crude Extracts of Tectona grandis L.f. against Wood DecayFungi

Wood is mainly made up of cellulose, hemicelluloses, lignin polymers and other organic and inorganic substances, making it susceptible to deteriorate by various biological agents. Tectona grandis L.f. (Teak) is a timberspecies with high resistance to biological deterioration, valued for its durability, beauty, and mechanical resistance.The purpose of this work was to evaluate the antifungal activity of crude extracts from teak on various fungi thatcause wood deterioration. For this, Teak heartwood was obtained, then fragmented and pulverized until obtaininga flour which was used for compounds extraction using the Soxhlet technique coupled to a rotary evaporatorthrough solvents of increasing polarity (hexane, dichloromethane, tetrahydrofuran, and acetone). The extractsobtained were tested against fungal organisms collected in the field, and the LC50 was determined using teak crudeextracts on Artemia salina as a biological model. The results obtained showed that a high flour yield was obtainedwith hexane (0.951 g), followed by tetrahydrofuran (0.446 g), dichloromethane (0.348 g), and acetone (0.152 g). Byusing nine fungal organisms that predominantly correspond to the genus Aspergillus, the extractable compoundswere tested, inhibiting 25% of mycelial growth with tetrahydrofuran (T. versicolor), and 40.9% with dichloromethane(G. trabeum). Likewise, the biological model of A. salina showed an LC50 of 84.9 μg/mL with hexane, 43.3 μg/mLwith dichloromethane, 59.6 μg/mL with tetrahydrofuran, and 54.7 μg/mL with acetone. For this reason, it is concluded that Teak wood contains many extractable compounds in relation to its weight, besides having antimicrobialactivity when extracted through polar compounds such as dichloromethane and tetrahydrofuran.

Participation of Auxin Transport in the Early Response of the Arabidopsis Root System to Inoculation with Azospirillum brasilense

The potential of Plant Growth Promoting Rhizobacteria(PGPR)has been demonstrated in the case of plant inoculation with bacteria of the genus Azospirillum which improves yield.A.brasilense produces a wide variety of molecules,including the natural auxin indole-3-acetic acid(IAA),as well as other phytoregulators.However,several studies have suggested that auxin induces changes in plant development during their interaction with the bacteria.The effects of A.brasilense Sp245 on the development of Arabidopsis thaliana root were investigated to help explain the molecular basis of the interaction.The results obtained showed a decrease in primary root length from the first day and remained so throughout the exposure,accompanied by a stimulation of initiation and maturation of lateral root primordia and an increase of lateral roots.An enhanced auxin response was evident in the vascular tissue and lateral root meristems of inoculated plants.However,after five days of bacterization,the response disappeared in the primary root meristems.The role of polar auxin transport(PAT)in auxins relocation involved the PGP1,AXR4-1,and BEN2 proteins,which apparently mediated A.brasilense-induced root branching of Arabidopsis seedlings.

Inhibitory Effect of N,N-Dimethylhexadecylamine on the Growth of White-Rot Fungus Trametes versicolor(L.)in Wood

Wood is an organic material that is a source of carbon of organisms called Wood-decay fungi,and to preserve the wood,various toxic compounds to man and the environment have been used.To analyze the effect of N,NDimethylhexadecylamine(DMHDA)on wood attacked by the rotting fungus Trametes versicolor L.We used an in vitro system to expose the fungus T.versicolor to different concentrations of the DMHDA(50,150 and 450µM).We quantified the diameter of mycelial growth and laccase activity,also,under these experimental conditions we studied morphological details of the organisms using different scanning equipment including scanning electron microscopy.The growth of T.versicolor exposed to DMHDA for 60 days,showed a concentration-dependent dose behavior,also,the electron microscopy analysis revealed that the morphology and mycelial density was affected by the DMHDA,showing a formation of atypical morphological and thickener folds.Finally,the pieces of wood treated with DMHDA and exposed to the fungus had a lower mass loss,after a period of 60 days of exposure,the values obtained were 0.7,1.0 and 0.5 g of mass lost for the control,LoC and LoDMHDA treatments respectively.Wood-rot fungi have represented economic losses worldwide,the strategies used have been supported by toxic compounds for the environment.The DMHDA both in the Petri dish system and as a wood preservative was shown to significantly inhibit the growth of T.versicolor.

DNA Fidelity: Expression of a Monocot Promoter in a Dicot Plant

The knowledge generated from the identification of plant promoters has been very important for plant biotechnology development. The use of promoters in transgenic plants allows a reasonable level of regulating protein expression. With the application of reporter genes, such as gusA (uidA,) the production of a colored protein, β-glucuronidase, can be detected and measured both qualitatively and quantitatively, and the activity of the promoter can be assessed. In this work we use a promoter of an abundant banana fruit protein gene Musa acuminata Acidic Chitinase class III a monocot species, to drive expression of gusA in a dicot species, like tomato. We evaluated the monocot promoter capabilities by localizing and quantifying β-glucuronidase (GUS) expression through fluorometric assays during tomato fruit ripening. Our results suggest that this promoter could be used for specifically strong fruit protein expression in dicot plants.