Biochemical and histological alterations of cellular metabolism from jerboa (Jaculus orientalis) by 2,4-dichlorophenoxyacetic acid: Effects on d-3-hydroxybutyrate dehydrogenase

2,4-Dichlorophenoxyacetic acid (2,4D) is one of the widely used herbicide of the phenoxy family with possible startling number of adverse effects on species other than the weeds which is designed to kill. The effects of 2,4D were investigated in jerboa (Jaculus orientalis), a wild animal of subdesert highlands. The jerboas have been daily treated intraperitonally with 2,4D 3 mg/kg body weight for 4 weeks. Plasmatic markers, and antioxidants defences systems were assessed and histological alterations were evaluated. The in vivo and in vitro effects of 2,4D on the mitochondrial d-3-hydroxybutyrate dehydrogenase (BDH) were also determined. Our results showed a strong decrease of triglycerides level and HDL cholesterol and an increase in GOT level and LDL cholesterol. The microscopic evaluation showed that 2,4D induced necrosis of seminiferous tubules cells in testis, hyperplasia of hepatocytes in liver and presence of multinucleated giant cells in brain. The results show also an inhibitory effect on BDH in terms of activity and kinetic parameters. All of these results show that 2,4D induces toxicity which affects energy metabolism, morphological perturbation and oxidative stress.     

Effect of taurine supplementation on the metabolism and body lipid‐to‐protein ratio in juvenile Atlantic salmon (Salmo salar)

Previously, we reported that methionine intake determined the taurine concentration in the liver of on‐growing Atlantic salmon fed plant protein diets. Further, the methionine intake and/or the increased taurine concentration following increased methionine intake affected the liver lipid metabolism. The following study therefore aimed to test whether taurine affected the growth or the type of growth when added in high plant protein diets naturally low in taurine but equal and adequate in dietary methionine. Juvenile Atlantic salmon [initial body weight (BW) of 2 g] were fed plant protein diets (16.5% fishmeal), which were supplemented with taurine or not for a period of 56 days. As a control for growth and normal metabolism, a fishmeal‐based commercial diet (68% fishmeal) was used. Supplementation with taurine to high plant protein diets had a slightly negative effect on weight gain, but the final body weight was not different. Interestingly, the pool of free amino acids in the liver and muscle was significantly higher in fish fed the supplemented diet as compared with fish fed the plant protein diet without taurine supplementation. Liver polyamine concentration was higher in fish fed the supplemented diet than in fish fed the similar diet without supplementation. Additionally, juvenile salmon fed the plant‐based diet supplemented with taurine had a lower body lipid‐to‐protein ratio due to a reduced whole‐body lipid content, while the whole‐body protein content was similar between treatments. Our study thus indicates that the addition of a low concentration of taurine to high plant protein diets interacts with lipid metabolism and storage, concomitantly affecting the general metabolism as the concentrations of the free amino acids and polyamines in the liver were significantly higher. The possible reasons for these changes are discussed.     

Titanium Dioxide Nanoparticle Circulation in an Aquatic Ecosystem

Nanotechnology is a dynamically developing field of scientific and industrial interest across the entire world, and the commercialization of nanoparticles (NPs) is rapidly expanding. Incorporation of nanotechnologies into a range of manufactured goods results in increasing concern regarding the subsequent release of engineered NPs into the environment. One of the biggest threats of using NPs is the transfer and magnification of these particles in the trophic chain. The aim of the studies was the evaluation of the distribution of TiO₂ NP contamination in the aquatic ecosystem under laboratory conditions. Bioaccumulation of TiO₂ NPs by plants (Elodea canadensis) and fish (Danio rerio) in the source of contamination was investigated. The studies were focused on the consequences of short-term water contamination with TiO₂ NPs and the secondary contamination of the components of the investigated model ecosystem (plants, sediments). It was found that in the fish and the plants exposed to NP contamination, the amount of Ti was higher than in the control, indicating an effective bioaccumulation of NPs or ions originating from NPs. It was clearly shown that the NPs present in the sediments are available to plants and fish. Additionally, the aquatic plants, an important trophic level in the food chain, can accumulate NPs and be a source of NPs for higher organisms. It was concluded that even an incidental contamination of water by NPs may result in long-term consequences induced by the release of NPs.     

Phenotypic and genetic characterization of Pseudomonas syringae strains associated with the recent citrus bacterial blast and bacterial black pit epidemics in Tunisia

In the spring of 2012, symptoms of a disease resembling citrus blast and citrus black pit were observed in some orchards in Tunisia. The epidemic spread rapidly in the following years. Twenty‐four commercial citrus orchards from four Tunisian regions showing characteristic symptoms of bacterial diseases were surveyed during a 3‐year study. Eighty‐eight Pseudomonas‐like bacterial isolates were successfully obtained from the northeast and west of Tunisia. No isolates were recovered from the central region. Overall, 46 isolates were identified as Pseudomonas syringae pv. syringae and most of them showed similar phenotypic and genetic profiles. The virulence of three selected isolates differed from one plant cultivar to another as well as from the type of plant organ used for the inoculation. In a bioassay test, all isolates produced syringomycin, which was confirmed by molecular detection based on the syrB and syrD genes. Only EC122 possessed syrD but not syrB. DNA fingerprints, based on repetitive sequence‐based polymerase chain reaction (rep‐PCR) and PCR melting profile (PCR MP), were used to determine the potential genetic diversity among strains. Clustering of PCR MP fingerprinting data matched with rep‐PCR fingerprinting data. The generated distribution tree showed that Tunisian isolates were closely related to the citrus reference strain LMG5496. In contrast, EC112, isolated from citrus, and the almond isolate EC122 were distantly related to the type strain LMG1247^T isolated from lilac. Such studies have not been reported until now for P. syringae from citrus.     

Enhancing Wheat Production Under Arid Climate Stresses Using Bio-Elicitors

Arid climate has contributed to crops yield production decrement in many regions due to water shortage and soil salinization. The main target of this research is to enhance wheat production under arid climate stresses by utilizing bio-elicitors. Two common wheat assortments i.?e. cv. Gemmiza 10 and Sakha 93 accomplished tolerant to these stresses utilizing bio elicitors include Acremonium coenophiulum, Streptomyces griseus, Trichoderma harzanium, T. viride, Rhodotorula glutinis, Paenibacillus polymyxa, Bacillus subtilis, B. megaterium, Pseudomonas putida, P. fluorescens compared with natural elicitors as methyl jasmonate (MJ), chitosan (CHI), ascorbic acid and putrescein (PUT). Varieties were planted in two progressive seasons in recently reclaimed lands, where two fields were selected the first is located in North Sinai while the second is situated to the south of Behira Governorate. Bio elicitors reduced abiotic stress and enhance physiological characteristic expressed as Proline, soluble carbohydrates %, Chl.a, Chl.b, Chl.a + b; Chl.a/Chl.b; Carotenoids and increased the concentration of Crude protein, N, P and total soluble carbohydrates in wheat grains. Using P. fluorescens exhibted increment in grain yield of wheat plants, cv sakha 93 amounted by 68.3% in Sinai region, while in Behira region the increement reached (45.5%) with P. polymyxa treatment. The response of Gemmiza 10 variety to the Bio-elicitors was less compared to Sakha 93 variety in both regions, where the highest increments due to P. putida treatment were18.9 and 19.7% in Sinai and beheirwa regions, respectively, compared to the control in each region. A remarkable increments of wheat growth, development and extended survival under salt and water limiting and restricting conditions. These findings demonstrate that wheat plants can display improved stress tolerance through bio-elicitors, and recommend that innovation may be useful in reducing effects of climate change and environmental stress on other crops and expanding agricultural production onto marginal lands.     

Analysis of Multiple Binary Responses Using a Threshold Model

Several discrete responses, such as health status, reproduction performance and meat quality, are routinely collected for several livestock species. These traits are often of binary or discrete nature. Genetic evaluation for these traits is frequently conducted using a single-trait threshold model, or they are considered continuous responses either in univariate or in multivariate context. Implementation of threshold models in the presence of several binary responses or a mixture of binary and continuous responses is far from simple. The complexity of such implementation is primarily due to the incomplete randomness of the residual (co)variance matrix. In the current study, a multiple binary trait simulation was carried out in order to implement and validate a new procedure for dealing with the consequences of the restrictions imposed to the residual variance using threshold models. Using three and eight binary responses, the proposed method was able to estimate all unknown parameters without any noticeable bias. In fact, for simulated residual correlations ranging from ?0.8 to 0.8, the resulting HPD 95% intervals included the true values in all cases. The proposed procedure involved limited additional computational cost and is straightforward to implement independent of the number of binary responses involved in the analysis. Monitoring of the convergence of the procedure must be conducted at the identifiable scale, and special care must be placed on the selection of the prior of the non-identifiable model. The latter could have serious consequences on the final results due to potential truncation of the parameter space.     

Alleviation of Salt Stress in Durum Wheat (Triticum durum L.) Seedlings Through the Application of Liquid Seaweed Extracts of Fucus spiralis

Many research studies have shown the importance of seaweed extract (SWE) in alleviating stress damage to plants. In this study, we examined the effect of liquid SWEs made from brown seaweed, Fucus spiralis, on germination, growth, antioxidant enzymes and some biochemical attributes of durum wheat under different levels of NaCl concentrations. Application of SWE at different concentrations (5, 10, 25, and 50%) significantly enhanced seed germination and growth parameters under salt stress, especially with 25% of seaweed liquid extract. Results show that the activity of antioxidant enzymes increased with increasing the algal extract concentration to 50%. Therefore, algal treatment is proved to be an effective technique to improve the growth of wheat seedlings under salt stress conditions. This study provides important information on the identification and utilization of seaweed resources for agriculture and it is the first study to report on the uses of this macroalgae as biostimulants in agriculture.

Abbreviations TG: total germination (%); SL: shoot length (cm); SFW: seedling fresh weight (g); SDW: seedling dry weight (g); TC: total carotenoids (mg/g.FW); TSP: total soluble proteins (mg/g.FW); SSC: soluble sugars content (mg/g.FW); TPC: (µg equivalent AG/mg DW); CAT: catalase (U mg^?1 protein); SOD: superoxide dismutase (U mg^?1 protein); APX: ascorbate peroxydase (U mg^?1 protein).     

Combined effect of deficit irrigation and potassium fertilizer on physiological response,plant water status and yield of soybean in calcareous soil

A 2-year field experiment (2013 and 2014) was conducted in calcareous soil (CaCO₃ 19.2%), on soybean grown under three irrigation regimes 100%, 85% and 70% of crop evapotranspiration combined with three potassium (K₂O) levels (90, 120 and 150 kg ha^?1). The objective was to investigate the complementary properties of potassium fertilizer in improving soybean physiological response under water deficit. Plant water status (relative water content RWC, chlorophyll fluorescence F_v/F₀ and F_v/F_m), had been significantly affected by irrigation or/and potassium application. Potassium improved growth characteristics (i.e. shoot length, number, leaf area and dry weight of leaves) as well as physiochemical attributes (total soluble sugars, free proline and contents of N, P, K, Ca and Na). Yield and yield water use efficiency (Y-WUE) were significantly affected by irrigation and potassium treatments. Results indicated that potassium application of 150 and 120 kg ha^?1 significantly increased seed yield by 29.6% and 13.89%, respectively, compared with 90 kg ha^?1 as average for two seasons. It was concluded that application of higher levels of potassium fertilizer in arid environment improves plant water status as well as growth and yield of soybean under water stress.     

Carrot root size distribution in response to biostimulant application

In 2009–2011, in Poland (53°13′N, 17°51′E), field experiments were conducted concerning the influence of biostimulants Kelpak SL and Asahi SL on the size grades of yield of carrot cv. ‘Karotan’. Kelpak SL is produced from seaweed Ecklonia maxima; Asahi SL is composed of nitrophenols. Biostimulants were sprayed from fourth-leaf stage of carrot, once, twice or three times in growing period. Seaweed extract was used at total doses of: 0, 2, 3, 4, 5, 6 and 7?l?ha^?1, while Asahi SL at 1?l?ha^?1. It was found that biostimulants had a favourable effect on total and commercial root yield, but this effect was dependent on the type of preparation, the dose, the time and the number of treatments. The best results in increasing the commercial yield were achieved after a single application of Kelpak SL at doses 2 or 3?l?ha^?1 at the fourth-leaf stage (13.1% and 12.4% respectively, compared to the control). Both biostimulants Kelpak SL and Asahi SL positively affected the root size distribution by increasing the yield of medium roots (1.9–3.8?cm in diameter) as well as large roots (3.8–5.0?cm), by 30.5% and 15.8%, respectively.