The ameliorating effects of polyamine supplement on physiological and biochemical parameters of Stevia rebaudiana Bertoni under cold stress

Stevia rebaudiana Bertoni is a perennial medicinal herb indigenous to tropical regions of South America. The present study evaluated some physiological changes of the plant under cold in the absence and the presence of polyamine conditions. The results showed photosynthetic pigments and photochemical efficiency of PSII reduced in cold treatment conditions than control, significantly. However, a considerable increase in the parameters was observed in all of polyamine treated goups. Leaf compatible solutes such as proline and glycine betaine that were not shown significantly increasing at cold treatment groups, elevated in the 2 days cold-polyamine-treated group. The similar results were seen for free amino acid and total protein contents of the treated plants. It was also revealed that specific activity of some antioxidant enzymes such as catalase and ascorbate peroxidase increased in cold-treated or cold + polyamine-treated groups than related controls. It caused a significant decrease in H₂O₂ and malondialdehyde contents of the treated plants. The results indicated an increasing in saturated long chain fatty acids after 4 days of cold at 4 °C. It was concluded that the polyamine supplement can induced a considerable tolerance in stevia plants at cold condition.     

Effects of fertilizers on plant diversity,density, and uniformity in Golestan rangelands

One of the management operations in rangeland ecosystems for pastures restoration and improvement is fertilizer application. This study was designed to investigate the effect of fertilizer (50 kg/ha urea and ammonium phosphate fertilizers) on species diversity changes in a 100-ha experimental field of Salmechal Rangeland, Golestan Province. Plant species mean canopy cover was recorded using a 50-m² sampling plot. Statistical analysis was performed using Excel 2007 and PAST software. Fertilizer application increased the number of species present in the region from 21 to 51 and the plant families from 11 to 23. The forbs had the highest proportion (54.91%) and bushes and shrubs had the lowest percentage in the region. Fertilizer application increased plant diversity, uniformity, and coverage of the grasses. There was a significant difference (p < 0.01) between the grass and forbs coverage before and after fertilizer treatments. The results showed that the biological and physiological growth periods of the annual and perennial plants were significantly different before and after fertilizer application (p < 0.01). Also, their proportion in rangeland plant species composition significantly increased after fertilizer application.     

The response of Stevia (Stevia rebaudiana Bertoni) to nitrogen supply under greenhouse condition

Stevia (Stevia rebaudiana Bertoni) is a perennial plant producing some natural sweeteners. Stevia is considered as a new crop in some countries. This study was conducted to find the stevia response to nitrogen fertilizer supply. Different levels of nitrogen (0, 30, 60, 90, 120, and 150 kg/ha from urea source) were used in a greenhouse condition and then the stevia growth and metabolites were assessed under different availability of nitrogen. Results showed that the optimum growth of stevia was obtained by 60 kg/ha nitrogen and more nitrogen supply did not enhance the stevia growth. It was observed that the total steviol glycosides (SVglys) content of Stevia was significantly increased by nitrogen fertilizer application just up to 30 kg/ha, while it decreased by more rates of nitrogen fertilizer. Our result clearly showed that SVglys yield reached to maximum value by application of 60 kg/ha of nitrogen fertilizer. Since the variation of SVglys content and shoot growth of the stevia were compromised by 60 kg/ha nitrogen, it can be concluded that 60 kg/ha of nitrogen fertilizer could be considered as an optimum rate of nitrogen for stevia and could also be recommended for greenhouse conditions.     

Impact of drought stress on yield,photosynthesis rate,and sugar alcohols contents in wheat after anthesis in semiarid region of Iran

Owing to the importance of after anthesis water deficit in Mediterranean regions (such as Iran), this study has focused on harmful impact of after anthesis drought stress on grain yield (GY), photosynthesis, and some physiological characteristics of wheat. To this aim, a factorial experiment based on randomized complete block design with three replications was used in greenhouse conditions in Razi University in Kermanshah city of Iran, during 2010–2011 growing season. Two bread wheat genotypes, “Zagros” (tolerant to drought) and “Marvdasht” (sensitive to drought) were grown in normal water supply condition (100% of field capacity) and drought stress from anthesis until maturity (50% of field capacity). The results indicated that after anthesis water deficit considerably reduced grain and biological yields, thousand grain weight (TGW) and a number of grains per spike (NGS) among different traits in genotypes. Under well-watered and drought-treated conditions, genotypes in terms of all evaluated traits had considerable variations. Water deficit caused more reduction of net photosynthesis rate (Pn), stomatal conductance (gs), relative water content (RWC) of leaf, chlorophyll a, b (Chl), and soluble proteins content in sensitive genotype; values were respectively 66.3, 73.2, 14.6, 32.1, 46.2, and 25.6%. Better performance of tolerant genotype under water deficit was associated with a great ability in production of some osmoprotectants as inositol, glycerol, and erythritol sugars. Rather adaptation of tolerant genotype to water deficit may be attributable to having maximum soluble protein, sugar alcohols, Chl content, RWC, gs and Pn in drought stress, and with respect to the results, wheat might not be able to synthesize mannitol. Transfer of gene(s) producing mannitol may cause more improvement of growth performance of wheat under stresses.     

Effect of growth regulators and explant on plant regeneration of Solanum lycopersicum L. var. cerasiforme

Tomato serves as a model to introduce agronomically important genes into dicotyledonous crop plants and to develop edible vaccines and produce cost-effective therapeutics. This study has developed an efficient protocol of shoot organogenesis for Lycopersicon esculentum Mill. through using of different types of explants and growth regulators. Generally, all explants responded significantly to presence of BAP. Best shoot regeneration for leaf (100%) was achieved on MS supplemented with BAP (2 mg/L) + IAA (0.1 mg/L), whereas it was recorded on MS supplemented with BAP (2 mg/L) and BAP (2 mg/L) + IAA (0.5 mg/L) for cotyledons (95%). In addition, hypocotyls (77%) showed the best shoot response on MS supplemented BAP (3 mg/L). Highest number of shoots per explant was 13.33, 12.25, 7.94 respectively for hypocotyls, leaves, cotyledons. The best medium for highest length of shoot was in the presence of BAP (3 and 2 mg/L) + IAA (0.1 mg/L) respectively for hypocotyl (45 mm) and leaf (40.50 mm) explants. This parameter was achieved for cotyledons (13.32 and 12.5 mm) on MS medium supplemented with BAP (3 and 2) mg/L + IAA (0.1 mg/L), respectively. The increasing of BAP concentration up to 3 (mg/L) causes shoot length to continue developing, but it fell down in the presence of BAP (4 mg/L) due to the toxic effect of growth regulators accumulation. Root formation took place within 10–14 days after culturing on the rooting media. Best root induction (100%) was observed on MS medium supplemented with IAA (0.1 and 0.2 mg/L). All rooted shoots acclimated in phytotron and then cultivated in the greenhouse.     

The necessity of antioxidant inclusion in caprine and ovine semen extenders: A systematic review complemented with computational insight

The inclusion of antioxidants (AOXs) has been proposed in various protocols to conserve the normal physiology of spermatozoa during (cryo) preservation. The main aim of this review was to understand the necessity of AOXs inclusion in semen extenders of caprine and ovine semen samples and to decipher physico-chemical space of AOXs used in semen extenders till now. A total 27 full-text relevant articles were finally discussed here. This systematic review showed that the inclusion of AOXs may improve the success of semen cryopreservation although at least three studies could not support this finding. AOXs have been not added after assaying total antioxidant capacity of the sample of interest, and this is principal measurement bias of all papers. Furthermore, no rational dose–response curve and precise posology have been considered in comparable studies. Furthermore, new methodologies are requested to detect the oxidative status of semen specimens before AXOs fortification and new methodologies like imaging are also needed to detect various injuries of sperms during semen (cryo)preservation. Defining computational chemical and physical spaces of AOXs which used in semen (cryo)preservation would be an interdisciplinary effort to hasten deciphering epoch-making compounds. In conclusion, more in-depth analytical, toxicological and pharmacological methodologies should be pursued in supplementation or addition of AOXs during caprine and ovine semen (cryo)preservation after determining the oxidative status of semen samples.     

Prunus arabica (Olivier) Meikle,an important genetic resource for breeding of almond: morphological and pomological characterizations

Genetic Resources and Crop Evolution - Phenotypic variation of 75 accessions of wild Prunus arabica (Olivier) Meikle species was assessed. There were significant variations among the accessions...     

Bioavailability and pharmacokinetic profile of levofloxacin following intravenous,intramuscular and oral administration in turkeys

1. The pharmacokinetics and bioavailability of levofloxacin in turkeys were investigated after a single intravenous (IV), intramuscular (IM) and oral (PO) administration of 10 mg/kg body weight.

2. The concentrations of levofloxacin in plasma samples were assayed using a microbiological assay method and pharmacokinetic parameters were calculated by non-compartmental analysis.

3. Following IV administration, the elimination half-life (t_0.5(β)), volume of distribution at steady state (Vd_ss) and total body clearance (Cl) were 4.49 h, 1.31 l/kg and 0.23 l/h/kg, respectively.

4. After single IM and PO administrations at the same dose, levofloxacin was rapidly absorbed as indicated by an absorption half-life (t_0.5ab) of 1.02 and 0.76 h, respectively; maximum plasma concentrations (C_max) of 5.59 and 5.15 μg/ml were obtained at a maximum time (T_max) of 2 h for both routes and levofloxacin bioavailability (F) was 96.5 h and 79.9% respectively after IM and PO administration. In vitro plasma protein binding of levofloxacin was 24.3%.

5. Based on these pharmacokinetic parameters, a dose of 10 mg/kg body weight given intramuscularly or orally every 24 h in turkeys can maintain effective plasma concentrations with bacterial infections with (minimum inhibitory concentration) MIC₉₀ > 0.1 μg/ml.     

Dissection of additive genetic variability for quantitative traits in chickens using SNP markers

The aim of this study was to separate marked additive genetic variability for three quantitative traits in chickens into components associated with classes of minor allele frequency (MAF), individual chromosomes and marker density using the genomewide complex trait analysis (GCTA) approach. Data were from 1351 chickens measured for body weight (BW), ultrasound of breast muscle (BM) and hen house egg production (HHP), each bird with 354 364 SNP genotypes. Estimates of variance components show that SNPs on commercially available genotyping chips marked a large amount of genetic variability for all three traits. The estimated proportion of total variation tagged by all autosomal SNPs was 0.30 (SE 0.04) for BW, 0.33 (SE 0.04) for BM, and 0.19 (SE 0.05) for HHP. We found that a substantial proportion of this variation was explained by low frequency variants (MAF <0.20) for BW and BM, and variants with MAF 0.10–0.30 for HHP. The marked genetic variance explained by each chromosome was linearly related to its length (R² = 0.60) for BW and BM. However, for HHP, there was no linear relationship between estimates of variance and length of the chromosome (R² = 0.01). Our results suggest that the contribution of SNPs to marked additive genetic variability is dependent on the allele frequency spectrum. For the sample of birds analysed, it was found that increasing marker density beyond 100K SNPs did not capture additional additive genetic variance.     

The effect of Zingiber Officinale Extract on Preventing Demyelination of Corpus Callosum in a Rat Model of Multiple Sclerosis

Background:Multiple sclerosis is the most prevalent neurological disability of young adults. Anti-inflammatory drugs have relative effects on MS. The anti-inflammatory and antioxidative effects of Zingiber officinale (ginger) have been proven in some experimental and clinical investigations. The aim of this study was to evaluate the effects of ginger extract on preventing myelin degradation in a rat model of MS. Methods: Forty nine male Wistar rats were used in this study and divided into four control groups: the normal group, cuprizone-induced group, sham group (CPZ + NaCMC), standard control group (fingolimod + cuprizone), including three experimental groups of CPZ, each receiving three different doses of ginger extract: 150, 300, and 600mg/kg /kg/day.Results:Ginger extract of 600 mg/kg prevented CC from demyelination; however, a significant difference was observed in the fingolimod group (p < 0.05). Difference in the CPZ group was quite significant (p < 0.05).Conclusion:Treatment with ginger inhibited demyelination and alleviated remyelination of corpus callosum in rats. Therefore, it could serve as a therapeutic agent in the MS.Key Words: Corpus callosum, Demyelination, Ginger extract, Multiple sclerosis, Rat