A mutation in the cytosolic O-acetylserine (thiol) lyase induces a genome-dependent early leaf death phenotype in <Emphasis Type="Italic">Arabidopsis</Emphasis>

Background  

Cysteine is a component in organic compounds including glutathione that have been implicated in the adaptation of plants to stresses. O-acetylserine (thiol) lyase (OAS-TL) catalyses the final step of cysteine biosynthesis. OAS-TL enzyme isoforms are localised in the cytoplasm, the plastids and mitochondria but the contribution of individual OAS-TL isoforms to plant sulphur metabolism has not yet been fully clarified.     

Wirkung von Deoxynivalenol beim wachsenden Schwein in Abhängigkeit von der Darreichungsform

To evaluate the minimum effective dose of pure DON leading to measurable losses in weight gain and feed consumption a special feeding experiment was created to compare the effect of DON in natural contaminated wheat and — for the first time — a non-cereal diet (potato) spiked with pure DON. Examined parameters were weight gain, feed consumption and blood parameters.Three trials were conducted. In the first trial a concentration of 4000 µg DON/kg feed was used. In the second and third trial we used concentrations of 4000 and 6000 µg DON/kg feed. Severe effects on feed consumption and weight gain were found only in the second trial (naturally contaminated wheat ad lib.). By contrast, no differences in any parameter were found in the first (restricted feeding) and third trial (non-cereal diet spiked with pure DON ad lib.).     

Modulation of nutrient acquisition and polyamine pool in salt-stressed wheat (Triticum aestivum L.) plants inoculated with arbuscular mycorrhizal fungi

Two wheat (Triticum aestivum L.) cultivars, Sids 1 and Giza 168, were grown under non-saline or saline conditions (4.7 and 9.4 dS m^?1) with and without arbuscular mycorrhizal fungi (AMF) inoculation. Salt stress considerably decreased root colonization, plant productivity and N, P, K⁺, Fe, Zn and Cu concentrations, while it increased Na⁺ level, particularly in Giza 168. Mycorrhizal colonization significantly enhanced plant productivity and N, P, K⁺, Fe, Zn and Cu acquisition, while it diminished Na⁺ uptake, especially in Sids 1. Salinity increased putrescine level in Giza 168, however, values of spermidine and spermine increased in Sids 1 and decreased in Giza 168. Mycorrhization changed the polyamine balance under saline conditions, an increase in putrescine level associated with low contents of spermidine and spermine in Giza 168 was observed, while Sids 1 showed a decrease in putrescine and high increase in spermidine and spermine. Moreover, mycorrhizal inoculation significantly reduced the activities of diamine oxidase and polyamine oxidase in salt-stressed wheat plants. Modulation of nutrient acquisition and polyamine pool can be one of the mechanisms used by AMF to improve wheat adaptation to saline soils. This is the first report dealing with mycorrhization effect on diamine oxidase and polyamine oxidase activities under salt stress.     

A portable system for collecting anatomical joint angles during stair ascent: a comparison with an optical tracking device

Background

Assessments of stair climbing in real-life situations using an optical tracking system are lacking, as it is difficult to adapt the system for use in and around full flights of stairs. Alternatively, a portable system that consists of inertial measurement units (IMUs) can be used to collect anatomical joint angles during stair ascent. The purpose of this study was to compare the anatomical joint angles obtained by IMUs to those calculated from position data of an optical tracking device.

Methods

Anatomical joint angles of the thigh, knee and ankle, obtained using IMUs and an optical tracking device, were compared for fourteen healthy subjects. Joint kinematics obtained with the two measurement devices were evaluated by calculating the root mean square error (RMSE) and by calculating a two-tailed Pearson product-moment correlation coefficient (r) between the two signals.

Results

Strong mean correlations (range 0.93 to 0.99) were found for the angles between the two measurement devices, as well as an average root mean square error (RMSE) of 4 degrees over all the joint angles, showing that the IMUs are a satisfactory system for measuring anatomical joint angles.

Conclusion

These highly portable body-worn inertial sensors can be used by clinicians and researchers alike, to accurately collect data during stair climbing in complex real-life situations.

     

Formulation of a novel oxybenzone-loaded nanostructured lipid carriers (NLCs)

The objective of the current study was to formulate oxybenzone into nanostructured lipid carriers (NLCs) to enhance its sunscreening efficacy and safety. NLCs of oxybenzone were prepared by the solvent diffusion method. A complete 2(3) factorial design was used for the evaluation of the prepared oxybenzone NLCs. The study design involves the investigation of the effect of three independent variables namely liquid lipid type (Miglyol 812 and oleic acid), liquid lipid concentration (15% and 30%), and oxybenzone concentration (5% and 10% with respect to total lipids) on the particle size (p.s.) , the entrapment efficiency (EE%) and the in vitro drug release after 8 h. The prepared NLCs were spherical in overall shape and were below 0.8 microm. Miglyol 812 and 30% liquid lipid were found to significantly decrease the p.s. and increase the EE% when compared to oleic acid and 15% liquid lipid. Increasing oxybenzone concentration increased significantly the p.s. but did not affect the EE%. NLCs prepared using Miglyol 812, 15% liquid lipid, and 10% oxybenzone showed slower drug release when compared to those prepared using oleic acid, 30% liquid lipid, and 5% oxybenzone, respectively. The candidate oxybenzone-loaded NLC dispersion was then formulated into gel. The incorporation of oxybenzone into NLCs greatly increased the in vitro sun protection factor and erythemal UVA protection factor of oxybenzone more than six- and eightfold, respectively, while providing the advantage of overcoming side effects of free oxybenzone as evidenced by very low irritation potential.     

In vitro evaluation of some bacterial isolates as biofertilizers and biocontrol agents against the second stage juveniles of <Emphasis Type="Italic">Meloidogyne incognita</Emphasis>

Representative soil samples were collected from soil apart and the rhizosphere of different plant varieties grown in five Egyptian Governorates. The presence of plant parasitic nematodes (PPN) and free living nematodes (FLN) in the collected samples were estimated. In addition, one hundred and 65 bacterial cultures which well known as biofertilizers (some are able to fix nitrogen and the others solubilize either phosphate or potassium) were isolated. The isolated bacteria were screened depending on their rate of growth. Thirty-five cultures of fast growing nitrogen fixing bacteria (NFB), phosphate solubilizing bacteria (PSB) and potassium solubilizing bacteria (KSB) and their cultural filtrates were tested in vitro as biocontrol agents against the second stage juvenile (J_2s) of the Meloidogyne incognita. In general, higher mortality percentages of nematodes were recorded by bacterial cultures than their comparative cultural filtrates. The highest mortality percentages were recorded by cultures of NFB7, PSB2 and KSB2 (100% at dilution 1/10), while it was 99.3, 99 and 97.8% at dilution 1/100, respectively. NFB7 exhibited a high nitrogen fixation rate (4.2 μmole N₂/mL/h), while PSB2 and KSB2 effectively solubilized phosphate and potassium comparing with the control treatments (1.94 fold of available phosphate and 2.0 fold of available potassium, respectively). NFB7, PSB2 and KSB2 isolates showed the highest protease, gelatinase and chitinase activities which were thought responsible for their nematicidal effect. The three bacterial isolates were identified as Paenibacillus polymyxa, Bacillus megaterium and Bacillus circulans, respectively.     

Dual Application of 24-Epibrassinolide and Spermine Confers Drought Stress Tolerance in Maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) by Modulating Polyamine and Protein Metabolism

No information is available concerning the influence of dual application of 24-epibrassinolide (EBL) and spermine (Spm) on the nitrogen metabolism in plants subjected to drought conditions. As a first report, this investigation assesses the role of EBL, Spm, and their dual application on polyamine and protein pools in water-stressed plants. It explores the ameliorative effects of these foliar applications under water deficiency. Two maize hybrids (Giza 10 and Giza 129) were treated with or without EBL and/or Spm foliar applications under well-irrigated and drought-stressed conditions (75 and 50 % of field capacity). Dual application (25 mg l^?1 Spm + 0.1 mg l^?1 EBL) significantly relieved the drought-induced inhibition on the activities of ribulose-1,5-bisphosphate carboxylase and nitrate reductase and the contents of relative water, nitrate, and protein, particularly in hybrid Giza 129. Changes in the content of free polyamines and in the activity of polyamine biosynthetic and catabolic enzymes were detected when water-stressed plants were treated with EBL and/or Spm. Putrescine content and arginine decarboxylase activity were significantly increased in stressed hybrid Giza 10 plants treated by the dual application. However, spermidine and Spm levels as well as ornithine decarboxylase and S-adenosylmethionine decarboxylase activities were significantly increased in stressed hybrid Giza 129 plants treated with the dual application. Diamine oxidase, polyamine oxidase, protease activity, carbonyl content, and ethylene formation were increased in response to water stress and significantly decreased when stressed plants were treated by the dual application. Total free amino acids, phenols, and flavonoids concentration were increased with the increasing water stress level; moreover, they further increased in stressed plants treated with the dual application. Overall, the combined utilization of EBL and Spm serves as complementary tools to confer plant drought tolerance by altering polyamine, ethylene, and protein levels.     

Synergistic larvicidal and repellent effects of essential oils of three Origanum species on Rhipicephalus annulatus tick

Ticks are of great economic importance worldwide, both because they represent major obstacles to livestock productivity and because of their ability to transmit diseases to humans and animals. Although synthetic acaricides are the most common method for tick control, their overuse has led to the development of resistance as well as unacceptable residual levels in animal products and in the environment in general. There is therefore an urgent need to identify alternative treatments. Among such alternative approaches for tick control is plant essential oil (EO) therapy. In the present study, we investigated the synergistic effect of EOs of three oregano species—Origanum onites, O. majorana and O. minutiflorum—against Rhipicephalus annulatus larvae. Gas chromatography–mass spectrometry profiles of the three EOs revealed that carvacrol was their major component, with a concentration of 86.2% in O. majorana, 79.1% in O. minutiflorum and 77.4% in O. onites. The results of larvicidal assays revealed that the doses that lead to the death of 50% of the ticks (LC₅₀) were 22.99, 25.08 and 27.06 µL/mL for O. majorana, O. minutiflorum and O. onites EOs, respectively, whereas the doses that lead to the death of 99% (LC₉₉) were 41.26, 43.62 and 48.96 µL/mL. In addition, the LC₅₀ and LC₉₉ of the three oils combined was lower (viz., 4.01 and 6.97 µL/mL) than that of each oil alone. The tested EOs were also able to repel larvae of R. annulatus to varying degrees, with O. onites oil exhibiting the greatest repellent effect, as shown by the lowest RC₅₀ dose, followed by O. minutiflorum and O. majorana. Interestingly, this means that the oil that was least effective in killing the larvae was the most effective in repelling them. The calculated synergistic factor of any combination was higher than 1 which means that combinations have a synergistic effect. In conclusion, the combination of all three oils showed higher toxic and repellent activities than either oil separately or combinations of any two oils, suggesting synergistic effects with low doses. Further studies including field trials and the establishment of the mode of action and side effects are urgently needed to expand on these findings, and other tick stages such as adults should also be tested.