Anti-mitotic and anti-genotoxic effects of Plantago lanceolata aqueous extract on Allium cepa root tip meristem cells

Plantago is the most important genus of Plantaginaceae family and is used in traditional medicine around the world for different purposes. Plantago coronopus L., Plantago major L., Plantago media L. and Plantago lanceolata L. are most commonly used species of Plantago in traditional medicine in Turkey. The main goal of this study was to investigate the eventual anti-mitotic and anti-genotoxic effects of P. lanceolata L. leaf aqueous extracts (15 g/L and 30 g/L) on Allium cepa L. root tip meristem cells which were treated with 0.7% hydrogen peroxide. For this purpose, two different experiments were performed under the same conditions. In the first experiment, Allium cepa onion bulbs were treated with 0.7% H₂O₂ for 1 h. After the H₂O₂ treatment, the onion bulbs were treated with two different concentrations (15 g/L and 30 g/L) of P. lanceolata extracts for 24 h. In the second experiment, A. cepa onion bulbs were treated with two different extract concentrations (15 g/L and 30 g/L) for 24 h and then with 0.7% H₂O₂ for 1 h. The test concentrations were determined according to doses which are recommended in alternative medicinal usage by people. As positive and negative control 0.7% H₂O₂ and tap water was used, respectively. As a result, it was determined that aqueous extracts reduced mitotic index and chromosome aberrations in treatment groups in comparison with controls. These results showed that P. lanceolata aqueous extracts have anti-mitotic and anti-genotoxic effects.     

Genotoxicity of Thermopsis turcica on Allium cepa L. roots revealed by alkaline comet and random amplified polymorphic DNA assays

This study was undertaken to evaluate genotoxic potential of Thermopsis turcica aqueous extracts on the roots of onion bulb (Allium cepa L.) by comet assay and random amplified polymorphic DNA technique. The Allium root growth inhibition test indicated that the EC₅₀ and 2×EC₅₀ values were 8 and 16 mg/ml concentrations of T. turcica aqueous extracts, respectively. The negative control (distilled water), positive control (methyl methane sulfonate, 10 mg/l) and 8 and 16 mg/ml concentrations of T. turcica extracts were introduced to the roots of onion bulbs for 24 and 96 h. The root growth, DNA damage in root cells and randomly amplified polymorphic DNA (RAPD) profiles of root tissue were used as endpoints of the genotoxicity. The comet assay clearly indicated that dose-dependent single strand DNA breaks in the root nuclei of onions were determined for the treatment concentrations of T. turcica extracts. In comparison to RAPD profile of negative control group, RAPD polymorphisms became evident as disappearance and/or appearance of RAPD bands in treated roots. The diagnostic and phenetic numerical analyses of RAPD profiles obviously indicated dose-dependent genotoxicity induced by Thermopsis extracts. In conclusion, the results clearly indicated that water extract of T. turcica has genotoxic potential on the roots of onion bulbs as shown by comet assay and RAPD technique.     

Hepatoprotective Potentials of Onion and Garlic Extracts on Cadmium-Induced Oxidative Damage in Rats

The hepatoprotective effect of onion and garlic extracts on cadmium (Cd)-induced oxidative damage in rats is reported. Control group received double-distilled water alone. Cd group was challenged with 3CdSO₄·8H₂O (as Cd; 1.5 mg/kg bw per day per oral) alone, while extract-treated groups were pretreated with varied doses of onion and/or garlic extract (0.5 and 1.0 ml/100 g bw per day per oral) for a week and thereafter co-treated with Cd (1.5 mg/kg bw per day per oral) for 3 weeks. Cd caused a marked (p?<?0.001) increase in the levels of lipid peroxidation and glutathione S-transferase, whereas glutathione, superoxide dismutase, and catalase levels were decreased in the liver. We also observed a decrease in hepatic activities of alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase and a concomitant increase in the plasma activities of ALT and AST. Onion and garlic extracts significantly attenuated these adverse effects of Cd. Onion extract proffered a dose-dependent hepatoprotection. Our study showed that Cd-induced oxidative damage in rat liver is amenable to attenuation by high dose of onion and moderate dose of garlic extracts possibly via reduced lipid peroxidation and enhanced antioxidant defense system that is insufficient to prevent and protect Cd-induced hepatotoxicity.     

Onion and garlic extracts lessen cadmium-induced nephrotoxicity in rats

Cadmium (Cd) is a well-known nephrotoxicant inducing kidney damage via oxidative stress. Since kidney is the critical target organ of Cd toxicity, this study was designed to evaluate the protective effects of onion (Allium cepa L.) and garlic (Allium sativum L.) aqueous extracts on Cd-induced renal oxidative stress in male Wistar rats. The control group received double distilled water alone and Cd group was challenged with 3CdSO₄ · 8H₂O (as Cd) (1.5 mg/100 g bw/day per oral) alone. Extract-treated groups were pre-treated with varied doses (0.5 ml and 1.0 ml/100 g bw/day per oral) of onion and/or garlic extract for 1 week after which they were co-treated with Cd (1.5 mg/100 g bw/day per oral) for 3 weeks. The results showed that the levels of renal lipid peroxidation (LPO) and glutathione-S transferase (GST) were significantly (P < 0.001) increased in rats that received Cd alone relative to the control group. More so, the levels of renal glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and Na⁺/K⁺-ATPase were significantly (P < 0.001) decreased in rats that received Cd alone. Treatment of Cd-intoxicated rats with varied doses of onion and/or garlic extract significantly (P < 0.05) restored the alterations in these parameters relative to the group that received Cd alone. While treatment with high dose of onion extract exerted a significant dose-dependent restoration of these parameters, treatment with high dose of garlic elicited a pro-oxidant effect, relative to their respective low dose. Our study suggests that onion and garlic extracts may exert their protective effects via reduction in LPO and enhanced antioxidant defense. These extracts may, therefore, be useful nutritional option in alleviating Cd-induced renal damage.     

Pectinases in Aqueous Extracts of Ditylenchus dipsaci

Aqueous extracts of a population of Ditylenchus dipsaci isolated from onion and maintained monoxenically on onion callus contained endo-polygalacturonase (endo-PG) and endo-pectinmethyltranseliminase (endo-PMTE). In viscometric tests pH 4.2 and 4.0 were optimal for degradation of sodium polypectate and pectin N.F., respectively, by endo-PG. Endo-PMTE reduced viscosity of pectin N.F. optimally at pH 8.5 or above. Activity was dependent on CaCl₂. Pectinmethylesterase activity was not detected in water, NaCl, or sucrose extracts of these nematodes. The extracts macerated potato tuber tissue, onion cotyledonary tissue, and strips of onion epidermis from the ventral surface of onion bulb scales at pH 4.2, 5.3, and 6.2. Pectin could not be localized with hydroxylamine-ferric chloride reagent in macerated tissues treated for 24 hr with active extract.     

Qualitative and Quantitative Analysis of Endogenous Gibberellins in Onion Plants and Their Effects on Bulb Development

Evidence has been reported that bulb development in onion plants (Allium cepa L.) is controlled by endogenous bulbing and anti-bulbing hormones, and that gibberellin (GA) is a candidate for anti-bulbing hormone (ABH). In this study, we identified a series of C-13-H GAs (GA₁₂, GA₁₅, GA₂₄, GA₉, GA₄, GA₃₄, and 3-epi-GA₄) and a series of C-13-OH GAs (GA₄₄, GA₂₀, GA₁ and GA₈) from the leaf sheaths including the lower part of leaf blades of onion plants (cv. Senshu-Chuko). These results suggested that two independent GA biosynthetic pathways, the early-non-hydroxylation pathway to GA₄ (active GA) and early-13-hydroxylation pathway to GA₁ (active GA), exist in onion plants. It was also suggested that GA₄ and GA₁ have almost the same ability to inhibit bulb development in onion plants induced by treatment with an inhibitor of GA biosynthesis, uniconazole-P. The endogenous levels of GA₁ and GA₄, and their direct precursors, GA₂₀ and GA₉, in leaf blades, leaf sheaths, and roots of 4-week-old bulbing and non-bulbing onion plants were measured by gas chromatography/selected ion monitoring with the corresponding [²H]labeled GAs as internal standards. In most cases, the GA levels in long-day (LD)-grown bulbing onion plants were higher than those of short-day (SD)-grown non-bulbing onion plants, but the GA₁ level in leaf blades of SD-grown onion plants was rather higher than that of LD-grown onion plants. Relationship between the endogenous GAs and bulb development in onion plants is discussed.     

Sensory interaction during trap-finding by female onion flies: implications for ovipositional host-plant finding

Using various three-dimensional traps alone and in combination with the onion volatile, dipropyl-disulphide (Pr₂S₂), we found that visual behaviour of female onion flies, Delia antiqua (Meigen), varied with the visual context (background composition and trap spacing) in which traps were presented and the females' reproductive state (mated vs. unmated). Against a background of real onions, females alighted more frequently on spherical than cylindrical traps, and white than green spheres, but females responded equally to white and green cylinders. In an onion field, baiting traps with Pr₂S₂ significantly increased female response to white over green traps, but had no influence on their response to trap shape. When traps were spaced 10 m apart and against a background of bare soil, females orienting to Pr₂S₂ baits alighted more frequently on vertical than horizontal traps, but shape and spectral reflectance were insignificant. However, when traps were spaced 0.25 m apart, females orienting to Pr₂S₂ baits alighted more frequently on cylinders than spheres. Mated females alighted more frequently on green than white cylinders, but unmated females responded to cylinders independent of spectral reflectance. When located 20 m downwind from Pr₂S₂ baits, mated females alighted on green cylinders significantly more often than unmated females. Response to traps mimicking onion plants suggests that ovipositional host-finding in female onion flies is dominated by olfactory responses at long range (several metres) and by visual cues at short-range (ca. 1 m). The view that host location by female onion flies is a hierarchical response pattern mediated by multiple sensory modalities and modified by resource level (habitat) and reproductive status, is discussed.     

Onion extract structural changes during in vitro digestion and its potential antioxidant effect on brain lipids obtained from low- and high-fat-fed mice

Abstract

This study investigated the effects of onion (Allium cepa, L.) extract on the antioxidant activity of lipids in low-and high-fat-fed mouse brain lipids and its structural change during in vitro human digestion. The onion extracts were passed through an in vitro human digestion model that simulated the composition of the mouth, stomach, and small intestine juice. The brain lipids were collected from low- and high-fat-fed mouse brain and then incubated with the in vitro-digested onion extracts to determine the lipid oxidation. The results confirmed that the main phenolics of onion extract were kaempferol, myricetin, quercetin, and quercitrin. The quercetin content increased with digestion of the onion extract. Antioxidant activity was strongly influenced by in vitro human digestion of both onion extract and quercetin standard. After digestion by the small intestine, the antioxidant activity values were dramatically increased, whereas the antioxidant activity was less influenced by digestion in the stomach for both onion extract and quercetin standard. The inhibitory effect of lipid oxidation of onion extract in mouse brain lipids increased after digestion in the stomach. The inhibitory effect of lipid oxidation of onion extract was higher in the high-fat-fed mouse brain lipids than that in the low-fat-fed mouse brain lipids. The major study finding is that the antioxidative effect of onion extract may be higher in high-fat-fed mouse brain lipids than that in low-fat-fed mouse brain lipids. Thus, dietary onion may have important applications as a natural antioxidant agent in a high-fat diet.     

Exogenous ethylene inhibits sprout growth in onion bulbs

Background and Aims

Exogenous ethylene has recently gained commercial interest as a sprouting inhibitor of onion bulbs. The role of ethylene in dormancy and sprouting of onions, however, is not known.

Methods

A cultivar (Allium cepa ‘Copra’) with a true period of dormancy was used. Dormant and sprouting states of onion bulbs were treated with supposedly saturating doses of ethylene or with the ethylene-action inhibitor 1-methylcyclopropene (1-MCP). Initial sprouting was determined during storage at 18 °C by monitoring leaf blade elongation in a specific size class of leaf sheaths. Changes in ATP content and sucrose synthase activity in the sprout leaves, indicators of the sprouting state, were determined. CO₂ and ethylene production of onion bulbs during storage were recorded.

Key results

Exogenous ethylene suppressed sprout growth of both dormant and already sprouting onion bulbs by inhibiting leaf blade elongation. In contrast to this growth-inhibiting effect, ethylene stimulated CO₂ production by the bulbs about 2-fold. The duration of dormancy was not significantly affected by exogenous ethylene. However, treatment of dormant bulbs with 1-MCP caused premature sprouting.

Conclusions

Exogenous ethylene proved to be a powerful inhibitor of sprout growth in onion bulbs. The dormancy breaking effect of 1-MCP indicates a regulatory role of endogenous ethylene in onion bulb dormancy.Key words: Bulb dormancy, Allium cepa, onion, sprout growth, ethylene, CO₂ production, respiration, 1-methylcyclopropene     

Quantitative analysis of ovipositional behavior: Effects of a host-plant chemical on the onion fly (Diptera: Anthomyiidae)

Behavioral responses of female onion flies, Delia antiqua (Meigen), to hostplant cues were quantified during encounters of individual flies with onion plants and onion foliar surrogates. The behavioral repertoire of such females included sitting, grooming, running up and down foliar surfaces, extension of the proboscis such that the labellum contacted foliar and soil surfaces, movements of the tip of the abdomen over surfaces (surface probing), subsurface probing of soil crevices with the ovipositor, and oviposition. Sequences of behaviors preceding oviposition were probabilistic rather than highly stereotyped but generally followed the order given above. Foliar surrogates were used to determine the effects of n-dipropyl disulfide (Pr₂S₂) on the sequence of behaviors leading up to oviposition. The addition of a Pr₂S₂-treated surrogate to a cage increased the frequency of alighting on that surrogate but also increased alighting on a nearby foliar surrogate without Pr₂S₂. After alighting, females encountering surrogates treated with Pr₂S₂ had shorter latencies to proboscis extension and surface probing, spent less time sitting and grooming, and had runs of shorter duration. These females were also more likely to make the transition from probing of surfaces of foliage and soil to subsurface probing of soil crevices and oviposition. Thus, rather than mediating a particular step in the behavioral sequence, Pr₂S₂ played a role throughout the sequence leading up to oviposition. Collectively, these data and past studies on the onion fly support the hypothesis that egglaying is triggered by a temporal summation of inputs to the central nervous system from various sensory modalities rather than strict behavioral chaining, with each transition effected by some unique cue.     

Evidence for nuclear-cytoplasmic incompatibility between Allium fistulosum and A. cepa

An F₂ population (Allium fistulosum x A. cepa) of 20plants, 10 BC₁,[(A. fistulosum x A. cepa) x A. cepa], and 50 BC₂ plants, [(A. fistulosum x A. cepa) x A. cepa] x A. cepa were studied cytogenetically and characterized for four isozyme alleles plus various morphological characteristics. All of the progenies were in A. fistulosum (the bunching onion) cytoplasm. In the F₂ population we observed non-random chromosomal and allelic segregation, suppression of bulb onion allelic expression, and abnormalities in mitosis and meiosis. Most BC₂ plants resembled A. cepa (the bulbing onion) morphologically, but anthers, filaments, pistils, and petals were abnormal. Only 3 plants, and these were most nearly like the F₁ hybrid morphologically, produced any seeds.The data and observations support the hypothesis of nuclear-cytoplasmic incompatibility interactions between the bunching and bulb onion species.Use of trade names does not imply endorsement of the products named nor criticism of similar ones not named. This research was supported by the New Mexico Agricultural Experiment Station.     

Genetics and molecular mapping of a novel purple blotch-resistant gene <Emphasis Type="Italic">ApR1</Emphasis> in onion (<Emphasis Type="Italic">Allium cepa</Emphasis> L.) using STS and SSR markers

Purple blotch (PB), caused by Alternaria porri (Ellis) Cifferi is the most devastating foliar disease of onion worldwide. However, no attempt has been made so far to detect or map a PB-resistant locus in the onion genome. The present investigation was performed to study the inheritance and develop molecular markers linked to PB resistance by using F₁, F₂, and BC₁ populations developed from a cross between the PB-resistant onion cultivar ‘Arka Kalyan’ and the susceptible parent ‘Agrifound Rose’. Disease evaluation with a virulent isolate of A. porri revealed that the F₁ was resistant while 498 F₂ plants segregated in a 3:1 resistant (R) to susceptible (S) phenotypic ratio and 128 BC₁ lines segregated in 1R:1S ratio, suggesting that the PB resistance is controlled by a single dominant gene designated as ApR1. Out of 288 ISSRs and SSRs primer sets, 59 distinguished the two parental lines and were used in bulk segregant analysis to link them with the presumed ApR1 gene. Seven markers viz. 3 ISSRs (AcISSR47₁₂₅₇, AcISSR68₁₆₀₀, and AcISSR103₁₄₁₆) and four SSRs (AcSSR7, AcSSR22, AcSSR31, and AcSSR33) showed specific polymorphism between resistant and susceptible bulks and were used for genotyping F₂ and BC₁ mapping populations. The three ISSR fragments were converted into sequence-tagged markers, and southern blotting confirmed their association with the resistant locus and the single-copy status. Molecular mapping revealed that the SSR marker AcSSR7 and STS marker ApR-450 were closely linked to the ApR1 locus in coupling at distances of 1.3 and 1.1 cM, respectively. Further, both of these markers could not be amplified in 23 susceptible onion genotypes with different genetic backgrounds. This is the first report of identification of markers linked to PB-resistant locus in onion. Hence, SSR marker AcSSR7 and STS marker ApR-450 identified in this study could be recommended for facilitating the introgression of ApR1 into susceptible onion variants for the development of high yielding PB-resistant genotypes.     

Induced tolerance of Sclerotium cepivorum to antibiotics in the presence of onion exudates

The onion white rot pathogen Sclerotium cepivorum was cultured on agar media containing 2% malt extract and one of the antifungal antibiotics, endomycin, griseofulvin, venturicidin and cycloheximide at concentrations that reduced but did not prevent growth of mycelium. When onion seeds or agar discs impregnated with diffusates from onion bulbs were placed on the antibiotic media, radial growth of the fungus was greatly increased, and there was a profuse development of aerial mycelium. Gaseous diffusates from onion tissue and from impregnated agar discs were also effective. On the antibiotic media, tomato, cabbage and radish seeds did not stimulate the growth of S. cepivorum and the onion exudates did not stimulate the growth of four other fungi. This and other evidence is considered to show that the stimulation of growth of S. cepivorum was not caused by any direct effect on the antibiotics but by a tolerance of the fungus to them, which was specifically induced by an exudate from its host plant. The phenomenon may be related to the reported reversal by onion extracts of the inhibitory effects of soil mycostasis on germination of sclerotia of the fungus.     

Predictability of multispecies competitive interactions in three populations of Atlantic salmon Salmo salar

Juvenile Atlantic salmon Salmo salar from three allopatric populations (LaHave, Sebago and Saint‐Jean) were placed into artificial streams with combinations of four non‐native salmonids: brown trout Salmo trutta, rainbow trout Oncorhynchus mykiss, Chinook salmon Oncorhynchus tshawytscha and coho salmon Oncorhynchus kisutch. Non‐additive effects, as evidenced by lower performance than predicted from weighted summed two‐species competition trials, were detected for S. salar fork length (L_F) and mass, but not for survival, condition factor or riffle use. These data support emerging theory on niche overlap and species richness as factors that can lead to non‐additive competition effects.     

Studies on fungi in the root region

Summary Aqueous extracts of adventitious roots ofAllium sativum L. (garlic), seedling roots ofAllium porrum L. (leek), and both adventitious and seedling roots ofAllium cepa L. (onion), were tested for antibiotic activity against three root-surface fungi,Cylindrocarpon radicicola Wollenw.,Gliocladium roseum (Link) Thom andFusarium culmorum (W. G. Smith) Sacc. by means of two different techniques.With a filter-paper disc technique, root extracts sterilised by membrane-filtration produced zones of inhibition of the test fungi, whereas root extracts sterilised by autoclaving showed no activity. Garlic root extract produced inhibition zones with all the test fungi, whereas extracts of onion adventitious roots and leek seedling roots produced inhibition zones with only one of the test fungi. The extract of onion seedling roots produced no inhibition zones. Root extracts of all theAllium species, when sterilised by membrane filtration, generally inhibited spore-germination of all the test fungi.     

Identification of Intermediates in the Formation of Onion Flavor

Headspace gas and ether extract of sliced or homogenized onion were analyzed by using GLC. Dialkyl disulfides, main components of characteristic flavor of sliced onion, were found to be very little when onion was homogenized. Addtion of NaBH₄ to the homogenate resulted in a marked production of disulfides while that of cysteine did not. SH compounds as cysteine and benzyl mercaptan were added to the homogenate to determine the intermediates which produced flavor with NaBH₄. The presence of propyl propanethiosulfinate, propanal and thiopropanal S-oxide was confirmed by isolation and identification of their sulfide derivatives.     

High-fat diet induces metabolic changes and reduces oxidative stress in female mouse hearts

After an acute myocardial infarction, obese patients generally have a better prognosis than their leaner counterparts, known as the “obesity paradox”. In addition, female sex is associated with a lower risk of cardiac ischemic events and smaller infarct size compared to males. The objective of the present work was to study the metabolic phenotype and mitochondrial function associated to female sex and short-term high-fat diet. ¹H NMR spectra of mice heart extracts were analysed by mRMR variable selection and linear discriminant analysis was used to evaluate metabolic changes. In separate experiments, O₂ consumption and H₂O₂ production were measured from isolated mitochondria as well as serum oxidation susceptibility. Fingerprinting showed that male hearts contained more myo-inositol, taurine and glutamate than female hearts. HFD reduced the levels of creatine, taurine citrate and acetate. Profiling showed increased alanine and fumarate in HFD suggesting altered glycolitic and Krebs cycle pathways. Female mice contained less glucose than males. Female sex nor HFD altered mitochondria oxygen consumption but both conditions reduced the amount of H₂O₂ produced in an additive manner. Serum of females had lower oxidation susceptibility than serum from males but there were no differences associated with HFD. In conclusion, female sex and short-term HFD have an effect on the myocardial metabolic pattern and reduce the amount of H₂O₂ produced by mitochondria in an additive manner suggesting different mechanisms of action. This could explain, at least in part, the protection afforded by female sex and the “obesity paradox”.     

Beneficial microorganism survival on seed, roots and in rhizosphere soil following application to seed during drum priming

Priming is a technique used to improve seedling establishment of direct-seeded crops such as onion and carrot, resulting in a quick and uniform emergence. This work investigated the application of four selected beneficial microorganisms (Pseudomonas chlororaphis MA342, Pseudomonas fluorescens CHA0, Clonostachys rosea IK726d11 and Trichoderma harzianum T22) to onion and carrot seed during drum priming, and their subsequent survival and establishment in the rhizosphere once the seed was planted. Different application rates of fungi (7 log₁₀ cfu g⁻¹ dry seed) and bacteria (6 log₁₀ cfu g⁻¹ dry seed) were required on onion to achieve the end target of 5 log₁₀ cfu g⁻¹ dry seed, whereas a lower rate (5 log₁₀ cfu g⁻¹ dry seed for both bacteria and fungi) was successful on carrot. Microorganism-treated seed was planted in soil in the glasshouse and root and rhizosphere soil samples were taken at 2, 4 and 8 weeks post-planting. All seed-applied microorganisms were recovered throughout the experiment, although differences in the survival patterns were seen. The bacterial isolates declined in number over time, with P. fluorescens CHA0 showing better overall survival than P. chlororaphis MA342, particularly on the roots and in the rhizosphere soil of carrot. In contrast to the bacteria, the fungal isolate C. rosea IK726d11 showed good survival on both onion and carrot, and increased significantly in number throughout the 8-week period. Trichoderma harzianum T22 remained relatively constant in number throughout the experiment, but showed better survival on carrot than onion roots. Similar results were found in three different soil-types.     

Pectolytic Enzymes in Three Populations of Ditylenchus dipsaci

Extracts of nematodes of the Raleigh, North Carolina (RNC), Waynesville, N. C. (WNC), and onion populations of Ditylenchus dipsaci were examined for pectolytic activity. RNC nematodes contained a NaCl-stimulated endo-polymethylgalacturonase with optimal pH for activity of 6.0, whereas nematodes of the WNC and onion populations possessed a NaCl-stimulated endo-polygalacturonase with pH optimum of 4.0. Nematodes of each population also contained a CaCl₂-activated endo-pectin methyl-trans-eliminase with optimal pH of 9.0. Nematode extracts containing 0.5 M NaCl macerated potato discs. RNC and onion nematodes induced gall formation in Wando pea seedlings, but WNC nematodes induced a resistant, hypersensitive response. Thus pectolytic activity was not correlated with pathogenicity of D. dipsaci on Wando pea.