RESUMEN
Insecticidal gene silencing by RNA interference (RNAi) involves a post-transcriptional mechanism with great potential for insect control. Here, we aim to summarize the progress on RNAi research toward control of insect pests in the Neotropical region and discuss factors determining its efficacy and prospects for pest management. We include an overview of the available RNAi information for Neotropical pests in the Lepidoptera, Coleoptera, Diptera, and Hemiptera orders. Emphasis is put on significant findings in the use of RNAi against relevant Neotropical pests, including diamondback moth (Plutella xylostella L.), Asian citrus psyllid (Diaphorina citri Kuwayama), and the cotton boll weevil (Anthonomus grandis Boheman). We also examine the main factors involved in insecticidal RNAi efficiency and major advances to improve screening of lethal genes, formulation, and delivery. Few studies detail resistance mechanisms to RNAi, demonstrating a need for more research. Advances in formulation, delivery, and resistance management tools for insecticidal RNAi in the Neotropics can provide a basis for efficient field application.
Asunto(s)
Hemípteros/genética , Control de Insectos/métodos , Mariposas Nocturnas/genética , Interferencia de ARN , Gorgojos/genética , Animales , América Central , Genes Letales , América del Sur , Clima TropicalRESUMEN
Las tubas uterinas (TU) son órganos tubulares fundamentales en la reproducción humana. No obstante, recién a mediados del siglo XVII con las investigaciones de Reinier De Graaf se comienza a develar su verdadera función en la reproducción. En este trabajo se resumen las principales contribuciones de Horacio Croxatto Avoni al conocimiento de la morfología y fisiología de la TU humana. Sus principales aportes tienen relación con la fisiología del transporte del cigoto y los gametos a lo largo de la TU.
The uterine tubes (UT) are fundamental tubular organs in human reproduction. However, it was not until the middle of the 17th century that Reinier De Graaf's research began to reveal its true role in reproduction. In this work the main contributions of Horacio Croxatto Avoni toward the knowledge of the morphology and physiology of the human UT are summarized. Its main contributions are related to the physiology of zygote transport and gametes throughout the UT.
Asunto(s)
Historia Antigua , Historia del Siglo XVI , Historia del Siglo XVII , Historia del Siglo XVIII , Historia del Siglo XIX , Historia del Siglo XX , Historia del Siglo XXI , Fisiología/historia , Trompas Uterinas , Anatomía/historiaRESUMEN
We analysed the association between a monogenean (Udonella cf. caligorum Johnston 1835) and its copepod host (Caligus sp.) living on a wild population of Arius herzbergii Bloch, 1794 in a north-eastern coastal lagoon from Venezuela. This study characterized infestation levels and analysed the effects of monogeneans on the fecundity and hatching success of the copepod host, as well as damage to its egg capsules and genital complex. A total of 218 Caligus specimens were analysed (94 males, 110 females and 14 immature stages) in which a total of 1017 monogeneans were found. These included 311 mature stages and 706 egg capsules. Monogenean stages were found attached to the cephalothorax, abdomen, genital complex and egg capsules of the copepods. No significant differences were found in fecundity and egg hatching when infested and non-infested ovigerous females were compared. No damage was observed on egg capsules or genital areas of infested ovigerous females. Our results suggest that this association, at the level of prevalence and intensity observed, is closer to commensalism than parasitism. The importance of considering that the nature of interaction is dynamic and changing with environmental conditions and time scale is highlighted.
Asunto(s)
Bagres/fisiología , Copépodos/parasitología , Interacciones Huésped-Parásitos , Trematodos/fisiología , Animales , Copépodos/anatomía & histología , Infestaciones Ectoparasitarias/epidemiología , Infestaciones Ectoparasitarias/parasitología , Fertilidad , Lagos/parasitología , Simbiosis , Venezuela/epidemiologíaRESUMEN
In this work, we investigated the usefulness of the SOS Chromotest for screening plant antigenotoxic agents against ultraviolet radiation (UV). Fifty Colombian plant extracts obtained by supercritical fluid (CO2) extraction, twelve plant extract constituents (apigenin, carvacrol, ß-caryophyllene, 1,8-cineole, citral, p-cymene, geraniol, naringenin, pinocembrin, quercetin, squalene, and thymol) and five standard antioxidant and/or photoprotective agents (curcumin, epigallocatechin gallate, resveratrol, α-tocopherol, and Trolox®) were evaluated for their genotoxicity and antigenotoxicity against UV using the SOS Chromotest. None of the plant extracts, constituents or agents were genotoxic in the SOS Chromotest at tested concentrations. Based on the minimal extract concentration that significantly inhibited UV-genotoxicity (CIG), five plant extracts were antigenotoxic against UV as follows: Baccharis nítida (16 µg mL-1) = Solanum crotonifolium (16 µg mL-1) > Hyptis suaveolens (31 µg mL-1) = Persea caerulea (31 µg mL-1) > Lippia origanoides (62 µg mL-1). Based on CIG values, the flavonoid compounds showed the highest antigenotoxic potential as follows: apigenin (7 µM) > pinocembrin (15 µM) > quercetin (26 µM) > naringenin (38 µM) > epigallocatechin gallate (108 µM) > resveratrol (642 µM). UV-genotoxicity inhibition with epigallocatechin gallate, naringenin and resveratrol was related to its capability for inhibiting protein synthesis. A correlation analysis between compound antigenotoxicity estimates and antioxidant activity evaluated by the oxygen radical absorbance capacity (ORAC) assay showed that these activities were not related. The usefulness of the SOS Chromotest for bioprospecting of plant antigenotoxic agents against UV was discussed.
Asunto(s)
Antimutagênicos/farmacología , Extractos Vegetales/química , Extractos Vegetales/farmacología , Protectores contra Radiación/farmacología , Rayos Ultravioleta/efectos adversos , Antimutagênicos/análisis , Baccharis/química , Hyptis/química , Lippia/química , Persea/química , Protectores contra Radiación/análisis , Solanum/químicaRESUMEN
This work was aimed to evaluate genotoxicity and antigenotoxicity activity against gamma-rays of a tannin fraction obtained from barks of Pinus caribaea, as well as to elucidate the antigenotoxic mechanisms involved in radioprotection by using different approaches as pre-, co- and post-irradiation cell treatments with plant extract. The tannin fraction was not genotoxic to Escherichia coli cells in experiments using different exposure times. This extract was antigenotoxic against gamma-rays when the cells were pre- or co-treated with this extracts, but not during post-irradiation treatments, suggesting a possibly antigenotoxic action through free radical scavenging mechanisms. The results are discussed in relation to the chemopreventive and therapeutic potential of the studied plant species.
Asunto(s)
Daño del ADN/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Escherichia coli/efectos de la radiación , Pinus/química , Taninos/farmacología , ADN Bacteriano/efectos de los fármacos , ADN Bacteriano/efectos de la radiación , Escherichia coli/genética , Rayos gamma , Pruebas de Mutagenicidad/métodos , Corteza de la Planta/química , Extractos Vegetales/aislamiento & purificación , Extractos Vegetales/farmacología , Extractos Vegetales/toxicidad , Protectores contra Radiación/aislamiento & purificación , Protectores contra Radiación/farmacología , Protectores contra Radiación/toxicidad , Taninos/química , Taninos/aislamiento & purificación , Taninos/toxicidadRESUMEN
The effect of sodium diethyldithiocarbamate (DDC) and S-2-aminoethyl-isothiouronicadenosin-5-triphosphate (adeturon) in the induction of Escherichia coli SOS response promoted by gamma-irradiation was studied by measuring the induction of sulA gene and the induction of lambda prophage. Furthermore, as a way of measure the exonuclease activity in gamma-irradiated cells in the presence or absence of both compounds, the DNA degradation was determined. Adeturon did not affected DNA degradation, but inhibited the induction of the SOS functions studied. On the contrary, DDC inhibited DNA degradation as well as the induction of the sulA gene, but enhanced lambda induction in E. coli lysogenic strains. These results indicate that both compounds diminish the DNA damage produced by gamma-irradiation and also suggest that the mechanisms of radioprotection must be different. Thus, radioprotection mediated by DDC should involve free hydroxyl radical scavenging and a minor activity of exonuclease. The enhancement of phage induction in E. coli cells that DDC produces could be attributed to its quelant effect and this would not be not probably directly related to radioprotection. Adeturon, as thiols, may serve also as scavenging agent of free hydroxyl radicals, diminishing indirectly the DNA damage level. In addition, adeturon must interact with DNA in the same form that other aminothiol compounds do it. This interaction, mediated by amino groups of adeturon, may serve to concentrate these compounds near of the DNA damage site, increasing the potential for the thiol portion of the molecule to donate hydrogen, decreasing the damage level on DNA molecule. However, adeturon do not modify the exonuclease activity. Some topic about the possible clinical application of both compounds are discussed.