Amelioration of indole acetic acid-induced cytotoxicity in mice using zinc nanoparticles biosynthesized with Ochradenus arabicus leaf extract

The diversity of natural phytochemicals represents an unlimited source for discovery and development of new drugs. Ochradenus arabicus, (family: Resedaceae) a notable medicinal plant displays a high content of flavonoid glycosides. This study investigates a possible preventative role of zinc nanoparticles biosynthesized by O. arabicus leaf extracts (OAZnO NPs) in limiting genotoxicity and cytotoxicity caused by indole acetic acid (IAA) in laboratory mice. ZnO NPs were synthesized using O. arabicus leaf extracts and characterized with UV–visible spectroscopy, scanning electron microscopy (SEM) and X-Ray diffraction (XRD). The mice were randomly distributed into the following six groups: control, OAZnO NPs treated (10 mg/kg BW), IAA treated (50 mg/kg BW); simultaneous treatment, pre-treatment, and post-treatment. Reactive oxygen species (ROS), DNA damage, chromosome aberration, and apoptosis were analyzed as toxicity endpoints. IAA exposure significantly induced production of ROS, DNA damage, apoptosis, chromosome aberrations, and micronuclei. Pre-, post-, and simultaneous treatment with OAZnO NPs ameliorated the damage caused by IAA exposure. Exposure to OAZnO NPs alone caused no toxicity for any endpoint based on comparison to controls. This study demonstrated that IAA-induced cytotoxic damage in mice could be ameliorated by treatment with OAZnO NPs. These findings require additional verification in mechanistic and in vitro studies.     

RNA metabolism during metamorphosis of Drosophila hydei

Determinations of total protein and RNA at various times after the beginning of the pharate pupal stage of Drosophila hydei, revealed an increase in both substances during the first 25 hr and a sudden decrease thereafter until 52 hr. From this time on the total amount of both protein and RNA increases slightly until emergence of the flies at 160 hr after the beginning of the pharate pupal stage. A similar pattern of changes was recorded for the total radioactivity as well as the specific activity of RNA labelled with ³H-uridine after the injection of the isotope immediately before the beginning of the pharate pupal stage.The migration profile of RNA labelled with ³H-uridine during larval development, revealed that shortly after the onset of the pharate pupal stage an essentially normal larval pattern consisting of major fractions of 28, 18, 8 to 9, and 4 to 7 S RNA. At 52 hr only the low molecular weight RNA was present. The ‘normal’ pattern was restored at the time of emergence of the flies, indicating re-utilization of degradation products of previously labelled RNA.     

Zn Subcellular Distribution in Liver of Goldfish (Carassius Auratus) with Exposure to Zinc Oxide Nanoparticles and Mechanism of Hepatic Detoxification

Zinc Oxide Nanoparticles (ZnO NPs) have attracted increasing concerns because of their widespread use and toxic potential. In this study, Zn accumulations in different tissues (gills, liver, muscle, and gut) of goldfish (Carassius auratus) after exposure to ZnO NPs were studied in comparison with bulk ZnO and Zn²⁺. And the technique of subcellular partitioning was firstly used on the liver of goldfish to study the hepatic accumulation of ZnO NPs. The results showed that at sublethal Zn concentration (2 mg/L), bioaccumulation in goldfish was tissue-specific and dependent on the exposure materials. Compared with Zn²⁺, the particles of bulk ZnO and the ZnO NPs appeared to aggregate in the environmentally contacted tissues (gills and gut), rather than transport to the internal tissues (liver and muscle). The subcellular distributions of liver differed for the three exposure treatments. After ZnO NPs exposure, Zn percentage in metal-rich granule (MRG) increased significantly, and after Zn²⁺ exposure, it increased significantly in the organelles. Metallothionein-like proteins (MTLP) were the main target for Zn²⁺, while MRG played dominant role for ZnO NPs. The different results of subcellular distributions revealed that metal detoxification mechanisms of liver for ZnO NPs, bulk ZnO, and Zn²⁺ were different. Overall, subcellular partitioning provided an interesting start to better understanding of the toxicity of nano- and conventional materials.     

Insecticidal Activity and Chemical Composition of Artemisia sieben Besser Essential Oil from Karaj,Iran

Atremisia sieberi Besser is a widely distributed plant that grows in many areas of Iran and has strong insecticidal activity against stored product pests, so an experiment was conducted to investigate fumigant toxicity of the A. sieberi oil collected from Karaj region of Iran. The oil was applied against one to seven day old adults of three major stored product insects including: Callosobruchus maculatus (Fab.), Sitophilus oryzae (L.), and Tribollium castaneum (Herbst). The potency of fumigant toxicity of A. sieberi on C. maculatus was higher (LC₅₀: 1.64 μL per L) than S. oryzae (LC₅₀: 4.41 μL per L) and T. castaneum (LC50: 20.31 μ.L per L). The relationships between the time exposure and oil concentration on mortality show that the mortality was increased as oil concentration and exposure time was increased. The concentration of 185 μL per L and exposure time of 24h was enough to obtain 100% kill of the insects. It was also found that the regions where A. sieberi grows affect essential oil components of the plant and can play an important role in properties of fumigant toxicity.     

Hormonal requirements for the larval-pupal transformation of the epidermis of Manduca sexta in vitro

In the tobacco hornworm, Manduca sexta, metamorphosis occurs in response to two releases of ecdysone that occur 2 days apart. Epidermis was explanted from feeding final-instar larvae before the first release of ecdysone and was cultured in Grace's medium. When exposed to 1 μg/ml of β-ecdysone for 24 hr and then to hormone-free medium for 24 hr, followed by 5 μg/ml of β-ecdysone for 4 days, the epidermis produced tanned pupal cuticle in vitro. During the first 24 hr of exposure to β-ecdysone, the epidermis first changed its cellular commitment to that for pupal cuticle formation (ET₅₀ = 14 hr), then later (by 22 hr) it became committed to tan that cuticle. Then, for most of the pupal cuticle to be tanned, at least a 12-hr period of culture in hormone-free medium was required before the cuticle synthesis was initiated. Consequently, some events prerequisite to sclerotization of pupal cuticle not only occur during the ecdysone-induced change in commitment but also during the ecdysone-free period. When the tissue was preincubated in 3 μg/ml of juvenile hormone (JH I or a mimic epoxygeranylsesamole) for 3 hr and then exposed to both ecdysone and juvenile hormone for 24 hr, it subsequently formed larval cuticle. The optimal conditions for this larval cuticle formation were exposure to 5 μg/ml of β-ecdysone in the presence of 3 μg/ml of epoxygeranylsesamole for 48 hr. When the epidermis was cultured in Grace's medium for 3 days and then exposed to 5 μg/ml of β-ecdysone for 4 days, 70% of the pieces formed pupal cuticle. By contrast, if both ecdysone and JH were added, 77% formed larval cuticle. Therefore, the change from larval to pupal commitment of the epidermal cells requires not only the absence of JH, but also exposure to ecdysone.     

Determination of synergistic effects of antibiotics and Zno NPs against isolated E. Coli and A. Baumannii bacterial strains from clinical samples

The mortality rates has been increased globally due to multidrug resistant (MDR) E.coli and A.baumanii bacterial strains and also there is an emerging resistance of the Enterobacteriaceae family of bacteria to Carbapenem antibiotics (CRE) in Saudi Arabia. The main aim of our research study is to isolate E.coli and A. baumannii bacterial species from various collected clinical samples and to evaluate the MIC and FICI of Colistin, Ciprofloxacin, Meropenem and ZnO NPs and in combination of Colistin, Ciprofloxacin, Meropenem with ZnO NPs.The clinical isolated strains of A. baumannii (MRO-17-13) and A. baumannii (MRO-17–25) was found to be sensitive towards colistin with 0.5 μg/mL concentration, whereas, all the isolated A. baumannii strains showed similar MIC value 2 mg/mL when tested with ZnO NPs, the MIC value for the ZnO NPs was found to be similar for all the E.coli strains 0.25 mg/mL. The effects of all Ciprofloxacin concentrations used in the study were bacteriostatic against E. coli (01UR19006568-01) strain but 1 mg/mL concentration of ZnO NPs alone is showed bactericidal activity, ZnO NPs effect was found to be concentration dependent, as highest concentration of ZnO NPs showed strongest antibacterial effect. In conclusion, more investigation is required to evaluate the acceptable concentration of Zno NPs and antibiotics selected to avoid toxicity and must be tested against more clinically isolated gram-negative bacterial strains.     

Differential net food utilization by larvae of Sitophilus oryzae and Sitophilus granarius

The net utilization of a meridic diet by Sitophilus oryzae from the newly hatched larva to the pupa was more efficient compared with that of S. granarius. The artificial diet was highly digestible to both species, but S. oryzae converted 24·1 per cent of the ingested food into body substance compared with 12·4 per cent converted by S. granarius. The mean pupal weight of S. granarius (1·402 mg) was greater than that of S. oryzae (1·012 mg); however, larvae of S. granarius consumed 2·6 times as much food and excreted 8·1 times as much faecal material to obtain that weight. Even though S. granarius consumed the diet at a greater rate, the relative growth rate of S. oryzae was faster. The intracellular symbiotes present in S. oryzae may have a rôle in the species' faster development and more efficient utilization of its food.     

Developmental changes in Malpighian tubule fluid transport

Developmental changes in Malpighian tubule fluid transport were studied using in vitro and in situ preparations from timed larval, pupal and adult skipper butterflies (Calpodes ethlius). The ability to transport fluid and the rate of fluid secretion depend on the developmental stage and the physiological state. Larval tubules are permanently switched on, do not require a diuretic hormone and transport fluid at an increasing rate as the larvae feed and grow. Fluid transport continues at larval-larval moults but is switched off 24 hr before pupal ecdysis. No secretory activity occurs during the first half of the pupal stage when the tubules are remodelled for adult function. The resumption of fluid transport midway through the pupal stage is in preparation for a rapid diuresis at adult emergence. High rates of fluid secretion are associated with feeding or drinking in adults.     

The cytotoxic targets of anatase or rutile + anatase nanoparticles depend on the plant species

The potential toxicity of nanoparticles (NPs) is under debate. Information about TiO₂ NPs phytotoxicity is still limited partly due to the different TiO₂ NP forms that may be found in the environment. The present work investigated the impact of different TiO₂ NPs forms (rutile and anatase) on germination, growth, cell cycle profile, ploidy level, and micronucleus formation in Lactuca sativa (lettuce) and Ocimum basilicum (basil). Seeds were exposed to anatase (ana) or rutile + anatase (rut+ana) at concentrations 5 - 150 mg dm^-3 for 5 d and after that different parameters were analyzed. Rut+ana showed high potential to impair germination and growth. On the other hand, ana alone showed a positive influence on seedling growth. Despite that, ana induced severe alterations in cell cycle dynamics. Regarding species, basil was more sensitive to TiO₂ NPs cytostatic effects (delay/arrest in G₀/G₁ phase), whereas in lettuce, TiO₂ NPs were more genotoxic (micronucleus formation increase). Finally, we propose that, besides germination and plant growth, cell cycle dynamics and micronucleus formation can be sensitive biomarkers of these NPs.     

The Response of Metallothionein and Malondialdehyde after Exclusive and Combined Cd/Zn Exposure in the Crab Sinopotamon henanense

The purpose of this paper is to show the interactions of Cd and Zn in the freshwater crab Sinopotamon henanense through metallothionein (MT) and malondialdehyde (MDA) level measurements. Laboratory acclimated S.henanense were exposed to Cd (50 µg/L, 100 µg/L, 500 µg/L ), and Zn (100 µg/L, 1000 µg/L) alone and in combined treatments (100 µg/L Zn+50 µg/L Cd, 100 µg/L Zn+100 µg/L Cd, 100 µg/L Zn+500 µg/L Cd, 1000 µg/L Zn+50 µg/L Cd, 1000 µg/L Zn+100 µg/L Cd, 1000 µg/L Zn+500 µg/L Cd) for 7, 14, 21, 28, 35 days. The results demonstrated that the MDA contents increased with exposure time and dose and showed time- and dose-dependence in both gills and hepatopancreas of S.henanense after single Cd exposure, while the changes of MDA levels were not significant with single Zn exposure. The MDA levels decreased when the crabs were exposed to metal mixtures compared to Cd exposure alone, indicating that Zn mediated the cellular toxicity of Cd. MT contents increased after single Cd exposure and also showed a time- and dose-dependence, in a tissue-specific way. Zn showed a limited ability of MT induction both in gills and hepatopancreas of S.henanense. The MT contents represented not a simple addition of single metal exposures but were enhanced at a higher concentration of Zn combined with different Cd concentrations compared to single metal exposure. Whether MT can be used as a biomarker for complex field conditions need to be considered cautiously since different induction patterns of MT were found among single Zn, Cd and combined groups. It is suggested that several biomarkers together as a suite should be used in the monitoring of heavy metal pollution in the aquatic environment.     

Detoxifying enzymes and the effects of temperature on the toxicity of malathion to Oncopeltus fasciatus (Heteroptera) and Tenebrio molitor (Coleoptera)

1. The effects of ambient temperature (T_a) on the toxicity of malathion to various life cycle stages of Tenebrio molitor and Oncopeltus fasciatus were investigated.2. Higher T_a (35°C) had a significant effect on toxicity, especially at concentrations above 70ppm. Nymphal stages of O. fasciatus were more susceptible than adults. The pupal stage of T. molitor was most resistant to combinations of high T_a and insecticide concentration.3. ld₅₀ ranged from 0.11 μg/insect to 0.23 (T. molitor), and 0.11 to 0.17 (O. fasciatus).4. Activity (μmol/min/mg protein) of carboxylesterase and glutathione S-transferase ranged from 0.72–1.97, and 0.47 to 1.35, respectively.     

Mechanisms of Toxicity of Ag Nanoparticles in Comparison to Bulk and Ionic Ag on Mussel Hemocytes and Gill Cells

Silver nanoparticles (Ag NPs) are increasingly used in many products and are expected to end up in the aquatic environment. Mussels have been proposed as marine model species to evaluate NP toxicity in vitro. The objective of this work was to assess the mechanisms of toxicity of Ag NPs on mussel hemocytes and gill cells, in comparison to ionic and bulk Ag. Firstly, cytotoxicity of commercial and maltose stabilized Ag NPs was screened in parallel with the ionic and bulk forms at a wide range of concentrations in isolated mussel cells using cell viability assays. Toxicity of maltose alone was also tested. LC50 values were calculated and the most toxic Ag NPs tested were selected for a second step where sublethal concentrations of each Ag form were tested using a wide array of mechanistic tests in both cell types. Maltose-stabilized Ag NPs showed size-dependent cytotoxicity, smaller (20 nm) NPs being more toxic than larger (40 and 100 nm) NPs. Maltose alone provoked minor effects on cell viability. Ionic Ag was the most cytotoxic Ag form tested whereas bulk Ag showed similar cytotoxicity to the commercial Ag NPs. Main mechanisms of action of Ag NPs involved oxidative stress and genotoxicity in the two cell types, activation of lysosomal AcP activity, disruption of actin cytoskeleton and stimulation of phagocytosis in hemocytes and increase of MXR transport activity and inhibition of Na-K-ATPase in gill cells. Similar effects were observed after exposure to ionic and bulk Ag in the two cell types, although generally effects were more marked for the ionic form. In conclusion, results suggest that most observed responses were due at least in part to dissolved Ag.     

Effects of meiosis-inhibiting agents and equine chorionic gonadotropin on nuclear maturation of canine oocytes

Experiments were conducted to determine the effects of meiosis-inhibiting-agents and gonadotropins on nuclear maturation of canine oocytes. The culture medium was TCM199 + 10 ng/ml epidermal growth factor supplemented with 25 microM beta-mercaptoethanol, 0.25 mM pyruvate, and 1.0 mM L-glutamine (Basal TCM). Initially, oocytes were cultured in Basal TCM alone or in Basal TCM + dibutylryl cyclic adenosine monophosphate (0.5, 1, 5, or 10 mM dbcAMP) for 24 hr. Dibutylryl cAMP inhibited resumption of meiosis in a dose-dependent manner; 60% of oocytes remained at the germinal vesicle (GV) stage after being cultured for 24 hr in 5 mM dbcAMP. The meiosis-inhibitory effect of dbcAMP appeared to be reversible, as the oocytes resumed meiosis and completed nuclear maturation after being cultured for an additional 48 hr in its absence. Oocytes were then cultured in Basal TCM alone or in Basal TCM + roscovitine (12.5, 25, or 50 microM) for 24 hr. Although approximately 60% of oocytes cultured in 25 microM roscovitine remained at the GV stage, this percentage was not significantly different from the 48% that also remained at the GV stage when cultured in its absence. Oocytes were cultured in Basal TCM + 25 microM roscovitine for 17 hr, exposed briefly to equine chorionic gonadotropin (eCG), and then cultured in Basal TCM for 48 hr. Short exposure of oocytes to eCG was beneficial, as it significantly increased the proportion of oocytes developing beyond germinal vesicle breakdown (P < 0.05) with approximately 20-30% of these were metaphase I (MI) oocytes. Study of the kinetics of nuclear maturation demonstrated that large numbers of oocytes remained at MI even after being cultured for 52 hr following brief exposure to eCG. This study showed that in vitro maturation of canine oocytes can be somewhat improved by short exposure of oocytes to eCG. However, further studies are still required to derive effective methods to mature canine oocytes in vitro.     

Antifungal activity of ZnO nanoparticles and their interactive effect with a biocontrol bacterium on growth antagonism of the plant pathogen Fusarium graminearum

Fungal plant pathogens such as Fusarium graminearum cause severe global economic losses in cereals crops, and current control measures are limited. This work addresses the potential for ZnO nanoparticles (NPs) and biocontrol bacteria to be used in plant fungal control strategies. Growth of F. graminearum was significantly (p = 0.05) inhibited by inclusion of the NPs in a mung bean broth agar and in sand. Suspension in mung bean broth medium modified the surface charge, dissolution, and aggregation state of the ZnO NPs, in comparison to processes occurring in water suspension. The ZnO NPs were significantly more inhibitory to fungal growth than micro-sized particles of ZnO, although both types of particles released similar levels of soluble Zn, indicating size-dependent toxicity of the particles. Zn ions produced dose-dependent inhibition, noticeable at the level of soluble Zn released from NPs after seven-day suspension in medium; inhibitory levels caused acidification of the growth medium. Transfer of fungal inoculum after exposure to the ZnO NPs to fresh medium did not indicate adaptation to the stress because growth was still inhibited by the NPs. The ZnO NPs did not prevent metabolites from a biocontrol bacterium, Pseudomonas chlororaphis O6, from inhibiting Fusarium growth: no synergism was observed in the mung bean agar. Because other studies find that soil amendment with ZnO NPs required high doses for inhibition of plant growth, the findings of pathogen growth control reported in this paper open the possibility of using ZnO NP-based formulations to complement existing strategies for improving crop health in field settings.     

Sublethal effects of Bacillus thuringiensis on the spruce budworm, Choristoneura fumiferana

Exposing larvae of the spruce budworm, Choristoneura fumiferana (Clemens), to sublethal ( 50% lethal dose) levels of Bacillus thuringiensis subsp. kurstaki at various stages of their development significantly increased development time to the pupal stage and reduced pupal size and number of eggs laid per female, but did not affect the proportion of embryonated eggs. The changes in larval development time, pupal weight and fecundity depended on the larval stage that was treated. Exposure of fourth instars delayed larval development and reduced only male pupal weights with no effects on fecundity. Exposure of sixth instars delayed larval development to a lesser extent than exposure of fourth instars but had a pronounced effect on weight of both male and female pupae. The effect on pupal weight was sex dependent, as males tended to be more affected than females. The reduction in male pupal weight did not appear to influence fecundity, because the effect of exposure was explained by the change in female pupal weight. Effects on larval growth and pupal weight were proportional to the dose that was ingested during exposure, and were observed at doses as low as one-tenth of the LD₅₀. Ingestion of an LD₅₀ caused a 29 or 45% delay in development of, respectively, female or male larvae when exposed as fourth instars and a 30% reduction in female pupal weight when larvae were exposed as sixth instars.     

Inhibitors of ester hydrolysis as synergists for biological activity of Cecropia juvenile hormone.

In Manduca sexta pupae the sensitivity to exogenous Cecropia C18 juvenile hormone (JH) is governed in large part by the rate at which the hormone is metabolized. By analysing the distribution of labelled JH and its metabolites, when dispensed by injection in light mineral oil, I have shown that the half-life of JH at concentrations ranging from 0·02 to 1 μg/g live weight of insect is approximately 24 hr.When the same doses of JH are dispensed in mineral oil containing endocrinologically inactive carboxylesterase inhibitors, organophosphate, and carbamate insecticides, the hormone's half-life in certain cases is prolonged significantly. The formulations containing those materials which most effectively prolong the hormone's half-life give higher assay scores than equivalent doses of hormone in mineral oil alone.From these results it is inferred that the chemicals tested synergize the Cecropia juvenile hormone's biological activity by serving presumably as inhibitors of the principal enzyme responsible for the rapid breakdown of exogenous C18-JH in haemolymph—a carboxylesterase. Preliminary in vitro experiments with carboxylesterase-rich Manduca pupal blood further support this inference.     

Control of cuticle formation by wing imaginal discs in vitro.

Wing discs from late final-instar Ephestia larvae form only pupal cuticle when immediately implanted into pupae which subsequently undergo metamorphosis. However, either pupal or adult structures are made in vitro depending on (1) the ecdysterone dose and/or (2) disc cell proliferation. Continuous culture in ecdysterone (0.5–5.0 μg/ml) results in the appearance of transparent cuticle. On the basis of several criteria, this untanned cuticle is postulated to be scaleless adult cuticle. Discs pulsed with 0.5 μg/ml ecdysterone for 48–120 hr, or with 5.0 μg/ml for 24 hr, formed tanned cuticle. Lower doses of ecdysterone (i.e., 0.5 μg/ml for 24 hr or continuous exposure to 0.05 μg/ml) trigger adult scale formation. Enhancement of [³H]thymidine incorporation by these latter doses suggests the occurrence of disc cell divisions and polyploidization. The choice between pupal and adult pathways by wing discs of this age can be controlled exclusively by ecdysterone; juvenile hormone need not be involved in vitro.     

Ecdysteroids and diapause in pupae of Heliothis punctiger

Most pupae of H. punctiger enter diapause when reared at 19°C, 12L:12D. When pharate pupae were treated for only 12 hr at 28°C about 50% developed at 19°C. The proportion of non-diapausing pupae increased as the temperature at which the pharate pupal stage was spent increased.The quantity of injected 20-hydroxyecdysone necessary to promote development in diapausing pupae varied from about 1 μg g^?1 soon after pupation to about 4 μg g^?1 after 50 days. It fell somewhat after 150 days.Removing brains from non-diapausing pupae showed that the brain secreted its hormone at the time of pupation (or just before). However, if the pupae were kept at 19°C development did not occur unless the brain remained in situ for at least 20 hr at 28°C. Implanting brains from non-diapausing pupae into diapausing ones had no measurable effect.These results may be explained by postulating that the prothoracic gland is ‘activated’ by exposure to high temperature, but that it reverts to inactivity over a period at 19°C. The ‘active’ gland must then be stimulated by brain hormone for a long period to trigger secretion of its hormone, which results in development. Diapause is thus the result of the failure of the prothoracic gland to secrete.     

The influence of some honeybee products as a diet substitute on the different stages of Coccinella undecimpunctata L. in Egypt

Several natural diets of honeybee products were tested for rearing Coccinella undecimpunctata L. under laboratory conditions. Two groups of tested adult and larval insect have been fed on the tested diets, the first group were fed on the tested honey bee products diets without adding aphids, while the second group fed on the same honeybee products with aphids added. The oviposition period in the first group was significantly shorter than control. The tested diets supplied with royal jelly + aphid and/or pollen grains + aphid caused the longest oviposition period. Diets of aphid alone and bee honey with aphid recorded the shortest oviposition period. Fecundity of ladybird was the highest in the tested diets with aphids than diets without aphid and/or aphid diet alone. The durations of larval and pupal stages were significantly different when compared with the diets with or without aphid and/or aphid diet alone. Further results indicated that the diets of royal jelly caused the shortest duration in larval and pupal stages.