Effects of <Emphasis Type="Italic">Prangos ferulacea</Emphasis> aqueous and hydroalcoholic extracts obtained from different organs on the regeneration of <Emphasis Type="Italic">Trifolium resupinatum</Emphasis>

Prangos ferulacea is one of the widely used, nutritional and popular fodders in livestock industry. This species is also considered as an important option in rangeland restoration and management. In this study, the comparative phytotoxic activity of aqueous and hydroalcoholic extracts obtained from different organs (flower, shoot and leaf) of P. ferulacea on proline content, seed germination and seedling growth of Trifolium resupinatum has been investigated. According to the results, the hydroalcoholic extract of P. ferulaceae flower possesses the highest total phenolic and flavonoid content and the uppermost phytotoxic effect on T. resupinatum. The extracts significantly decreased seed germination and seedling growth of T. resupinatum and increased the proline content. Our findings indicate that hydroalcoholic extract induced a stronger oxidative stress in T. resupinatum. Finally, based on the results, aqueous allelochemicals that originated from P. ferulacea played a significant role in the successful propagation and development of T. resupinatum in rehabilitated pastures. According to our results, the phytotoxicity effect of the hydroalcoholic extract was significantly higher than that of the aqueous extract. Since in nature, the allelopathic interaction between plants is closer to the aqueous method, primary evaluations of rangeland restoration using this method is suggested.     

Combined detection and introgression of QTL in outbred populations

Background

Detecting a QTL is only the first step in genetic improvement programs. When a QTL with desirable characteristics is found, e.g. in a wild or unimproved population, it may be interesting to introgress the detected QTL into the commercial population. One approach to shorten the time needed for introgression is to combine both QTL identification and introgression, into a single step. This combines the strengths of fine mapping and backcrossing and paves the way for introgression of desirable but unknown QTL into recipient animal and plant lines.

Methods

The method consisting in combining QTL mapping and gene introgression has been extended from inbred to outbred populations in which QTL allele frequencies vary both in recipient and donor lines in different scenarios and for which polygenic effects are included in order to model background genes. The effectiveness of the combined QTL detection and introgression procedure was evaluated by simulation through four backcross generations.

Results

The allele substitution effect is underestimated when the favourable QTL allele is not fixed in the donor line. This underestimation is proportional to the frequency differences of the favourable QTL allele between the lines. In most scenarios, the estimates of the QTL location are unbiased and accurate. The retained donor chromosome segment and linkage drag are similar to expected values from other published studies.

Conclusions

In general, our results show that it is possible to combine QTL detection and introgression even in outbred species. Separating QTL mapping and introgression processes is often thought to be longer and more costly. However, using a combined process saves at least one generation. With respect to the linkage drag and obligatory drag, the results of the combined detection and introgression scheme are very similar to those of traditional introgression schemes.     

Variation in the Essential Oil Composition,Antioxidant Capacity,and Physiological Characteristics of Pelargonium graveolens L. Inoculated with Two Species of Mycorrhizal Fungi Under Water Deficit Conditions

In recent years, the application of arbuscular mycorrhizal fungi (AMF) has been considered to be an important strategy for improving crop yield and quality. In the present study, a factorial experiment based on a complete randomized design with two factors was performed to investigate the effect of AMF and water stress on the essential oil (EO) composition, antioxidant activity, and physiological and morphological characteristics of rose-scented geranium (Pelargonium graveolens L.). The factors included AMF inoculation (Rhizophagus intraradices, Funneliformis mosseae, and a mixture of both species) and irrigation levels [well-watered (WW), moderate drought stress (MDS), and severe drought stress (SDS)]. The main EO constituents were citronellol (31–37%) and geraniol (9–14%) in all treatments. Under water-stress conditions, some constituents increased, such as geraniol and geranyl formate, whereas others decreased, such as linalool, menthone and rose oxide. Overall, the highest amount of citronellol (37.3%) and geraniol (14.8%) was obtained in the plants inoculated with F. mosseae and R. intraradices under WW and MDS conditions, respectively. Antioxidant activity, total flavonoids, and phenolics were increased because of AMF inoculation, whereas a different trend was observed for the phenolic and flavonoid contents under water-stress conditions. Furthermore, water deficit elevated the amount of soluble carbohydrates as well as the proline content, whereas the amount of proline was lower in inoculated plants than in non-inoculated ones. All the growth parameters were improved in the AMF-inoculated plants compared to non-inoculated ones under different irrigation regimes. Drought conditions decreased the photosynthetic pigments and efficiency, whereas AMF plants ameliorated the adverse effect of drought conditions. In general, mycorrhizal inoculation resulted in an improvement in the growth parameters as well as the phytochemical and physiological characteristics of rose-scented geranium.

     

Thermodynamic of Water Sorption of Grape Seed: Temperature Effect of Sorption Isotherms and Thermodynamic Characteristics

After determination of sorption isotherms of grape seeds using gravimetric method, five models with temperature effect were used to fit water sorption isotherms of grape seeds to investigate temperature effect on sorption isotherms and its thermodynamic characteristics. Halsey model had minimum mean relative percentage error (M _e ) and all other models used were good in fitting experimental data (with M _e of less than 10 %). Differential parameters such as net isosteric heat, isosteric heat, differential entropy and integral function such as equilibrium heat, net equilibrium heat, integral entropy and surface potential have been calculated. The net isosteric heat, isosteric heat and differential entropy decreased with moisture content. The net equilibrium enthalpy, equilibrium enthalpy and integral entropy decreased with moisture content. The surface potential at four temperatures (35, 45, 55 and 65 °C) was estimated, and low temperature effect was reported.     

Protective role of tebuconazole and trifloxystrobin in wheat (Triticum aestivum L.) under cadmium stress via enhancement of antioxidant defense and glyoxalase systems

Cadmium (Cd) is a toxic metal and an environmental pollutant that significantly reduces plant growth and productivity. Proper management can ameliorate dysfunction and improve the plant growth and productivity exposed to Cd. Therefore, the present study was conducted to explore the protective role of the fungicides tebuconazole (TEB) and trifloxystrobin (TRI) in helping wheat (Triticum aestivum L. cv. Norin 61) seedlings to tolerate Cd. Five-day-old hydroponically grown seedlings were allowed to mild (0.25 mM CdCl₂) and severe (0.5 mM CdCl₂) Cd stress separately and with the fungicides (2.75 µM TEB + 1.0 µM TRI) for the next four days. Compared to control, the level of H₂O₂ in the seedlings exposed to mild and severe Cd stress alone increased by 81 and 112%, respectively. The accumulation of Cd also increased in the wheat seedlings along with declining mineral nutrients under Cd stress. The protective effect of TEB and TRI was observed with the enhancement of the antioxidant defense and methylglyoxalase systems and reduction in oxidative damage. Applying TEB and TRI reduced MDA (by 9 and 18%), EL (by 21 and 17%), MG (by 12 and 17%), and LOX activity (by 37 and 27%), respectively, relative to Cd stress alone. Cadmium uptake also decreased in the shoots (by 48 and 50%, respectively) and roots (by 23 and 25%, respectively) of the fungicide-treated wheat seedlings under mild and severe Cd stress, relative to stress alone. These results indicate the exogenous application of TEB and TRI is a promising approach to improve Cd tolerance in wheat plants. Further investigation is needed under field conditions and for other crop species to determine the Cd-tolerance induced by TEB and TRI application.     

Galactosylated collagen matrix enhanced in vitro maturation of human embryonic stem cell-derived hepatocyte-like cells

Due to their important biomedical applications, functional human embryonic stem cell-derived hepatocyte-like cells (hESC-HLCs) are an attractive topic in the field of stem cell differentiation. Here, we have initially differentiated hESCs into functional hepatic endoderm (HE) and continued the differentiation by replating them onto galactosylated collagen (GC) and collagen matrices. The differentiation of hESC-HE cells into HLCs on GC substrate showed significant up-regulation of hepatic-specific genes such as ALB, HNF4α, CYP3A4, G6P, and ASGR1. There was more albumin secretion and urea synthesis, as well as more cytochrome p450 activity, in differentiated HLCs on GC compared to the collagen-coated substrate. These results suggested that GC substrate has the potential to be used for in vitro maturation of hESC-HLCs.     

In vivo and in vitro management of Meloidogyne incognita (Tylenchida: Heteroderidae) using rhizosphere bacteria,Pseudomonas spp. and Serratia spp. compared with oxamyl

Biological control using rhizosphere bacteria, Pseudomonas spp. and Serratia spp. is a prospective alternative technique to overcome plant parasitic nematodes infection. So, the current study was conducted in vitro on five egg-masses, 100 free eggs and 100 infective juveniles (IJs) of Meloidogyne incognita as well as greenhouse treatments on Luffa aegyptiaca L. to evaluate the nematicidal potential of six strains belong to Pseudomonas spp. and Serratia spp. as compared to oxamyl.Results showed that the inhibitory effect and juvenile mortality varied according to bacteria species, strains and exposure time. All the tested bacteria significantly (P ≤ 0.05) inhibited egg hatching and increased juvenile mortality in vitro. After 3 days of treatment, Pseudomonas spp. were more effective against eggs (48.31to 55.15%) and IJs (20.98 to 25.30%) than Serratia spp. (44.55 to 49.75% with eggs) and (19.06 to 21.61% with IJs), respectively. In the pot experiment, Luffa aegyptiaca L. treated with Serratia spp. and Pseudomonas spp. displayed significantly higher (P ≤ 0.05) levels of growth (as indicated by root length, fresh roots weight and fresh shoots weight) compared to control plants and significantly (P ≤ 0.05) suppressed galling (number of galls) and reproduction (as indicated by number of egg-masses on roots and number of eggs and juveniles in pot soil). Meanwhile, among the treated plants, Serratia spp. and Pseudomonas spp. gave the best results in shoot weight of pots infected by eggs of M. incognita than those infected with IJs as compared with positive control. While, oxamyl treatment gave the best results in pots infected by eggs and IJs.The lowest galling (gall index), number of eggs and juveniles in soil was observed in the treatment with mixture of Serratia spp. and Pseudomonas spp. as well as, enhanced growth of sponge gourd more than application each of them alone. Pots treated with oxamyl overwhelmed those treated with mixture of Serratia spp. and Pseudomonas spp.     

Viscoelasticity of Tau Proteins Leads to Strain Rate-Dependent Breaking of Microtubules during Axonal Stretch Injury: Predictions from a Mathematical Model

The unique viscoelastic nature of axons is thought to underlie selective vulnerability to damage during traumatic brain injury. In particular, dynamic loading of axons has been shown to mechanically break microtubules at the time of injury. However, the mechanism of this rate-dependent response has remained elusive. Here, we present a microstructural model of the axonal cytoskeleton to quantitatively elucidate the interaction between microtubules and tau proteins under mechanical loading. Mirroring the axon ultrastructure, the microtubules were arranged in staggered arrays, cross-linked by tau proteins. We found that the viscoelastic behavior specifically of tau proteins leads to mechanical breaking of microtubules at high strain rates, whereas extension of tau allows for reversible sliding of microtubules without any damage at small strain rates. Based on the stiffness and viscosity of tau proteins inferred from single-molecule force spectroscopy studies, we predict the critical strain rate for microtubule breaking to be in the range 22–44 s⁻¹, in excellent agreement with recent experiments on dynamic loading of micropatterned neuronal cultures. We also identified a characteristic length scale for load transfer that depends on microstructural properties and have derived a phase diagram in the parameter space spanned by loading rate and microtubule length that demarcates those regions where axons can be loaded and unloaded reversibly and those where axons are injured due to breaking of the microtubules.