Evaluation of grain yield indices in hexaploid wheat genotypes in response to drought stress

Drought stress limits crop production in the world. Therefore, employing high-yielding cultivars tolerant to drought is an effective approach to reduce its detrimental effects. To identify drought-tolerant genotypes, 36 wheat genotypes were evaluated during the 2010–2011 and 2011–2012 growth seasons. A field experiment was conducted in a split-plot design with two irrigation treatments (100% field capacity (FC) until harvest and no irrigation after anthesis) as main plots in three replications and genotypes as subplots. Grain yield, its components and drought tolerance indices were measured. Results showed a significant reduction in yield and its components under drought conditions. Grain yield had significant positive correlations with stress tolerance index (STI), mean productivity (MP) index and geometric mean productivity (GMP), while it was negatively correlated with stress susceptibility index (SSI) and tolerance index (TOL) under stress condition. These results indicated that superior genotypes could be selected based on high values of STI, MP and GMP and low value of SSI. The results were validated by principal component analysis (PCA) as it showed genotypes with high PC1 and low PC2 were more desirable. Based on the results, genotypes number 8, 11, 17, 30, 34 and 35 were recognized as suitable for both conditions.     

The Highlighted Roles of Metabolic and Cellular Response to Stress Pathways Engaged in Circulating hsa-miR-494-3p and hsa-miR-661 in Alzheimer’s Disease

Background:Among different roles of miRNAs in AD pathogenesis, hsa-miR-494-3p and hsa-miR-661 functions are poorly understood. Methods:To obtain the gene targets, gene networks, gene ontology, and enrichment analysis of the two miRNAs, some web servers were utilized. Furthermore, the expressions of these miRNAs were analyzed by qRT-PCR in 36 blood sera, including 18 Alzheimer’s patients and 18 healthy individuals. Results:The in silico analysis demonstrated the highlighted roles of metabolic and cellular response to stress pathways engaged in circulating hsa-miR-494-3p and hsa-miR-661 in AD. The qRT-PCR analysis showed that the downregulated expression level of hsa-miR-661 was statistically significant (p < 0.05). Also, the ROC curve of hsa-miR-661 displayed the significant AUC (p = 0.01). Conclusion:Based on our findings, the metabolic and cellular responses to stress pathways are closely connected to these two miRNAs functions. Besides, the qRT-PCR and Roc curve determined hsa-miR-661 could be as a biomarker for diagnosis or prognosis of AD patients. Key Words: Alzheimer’s disease, Serum, Circulating microRNAs     

Analysis of genetic diversity in a collection of Plantago species: application of ISSR markers

Journal of Crop Science and Biotechnology - The analysis of genetic diversity in medicinal plant species can greatly facilitate germplasm conservation and selection for use in breeding schemes. The...     

Infection experiments of Pyrenophora teres f. maculata on cultivated and wild barley indicate absence of host specificity

European Journal of Plant Pathology - It is important to investigate the possibility of pathogen transmission between cultivated and uncultivated hosts due to the role of the latter in pathogen...     

Effect of Photoperiod Manipulation on Growth Performance,Physiological and Hematological Indices in Juvenile Persian Sturgeon,Acipenser persicus

The effect of five different light regimes on growth, stress and hematological indices was studied in Persian sturgeon, Acipenser persicus. Fish with average weight of 645.3 ± 11.2 g were subjected to different photoperiods (24 L, 12 L:12 D, 16 L:8 D, 8 L:16 D and 24 D) for 8 wk. Blood samples were collected at the end of the experiment for measuring cortisol, glucose and hematological features. The whole growth parameters showed no significant difference. Plasma cortisol concentration was significantly higher in 12 L:12 D, while the lowest level was observed in fish exposed to 24 D. No significant changes were observed among the treatments for glucose concentration. Lactate concentration varied significantly among the treatments. Some hematological indices including hematocrit and number of white blood cells were affected by different light regimes, but the others (hemoglobin and number of red blood cells) were not affected significantly. The results showed that photoperiod manipulation can alters some stress‐related metabolites and may enhance growth rate in fish exposing to continuous darkness.     

Identification of the leaf rust resistance genes Lr9, Lr26, Lr28, Lr34, and Lr35 in a collection of Iranian wheat genotypes using STS and SCAR markers

Brown rust or leaf rust is one of the most important diseases of wheat occurring almost in all wheat-producing regions and reduces crop yield. In order to produce resistant cultivars, it is necessary to identify resistance genes in different germplasms and combine them in (a) suitable stock(s). To identify the presence of the leaf rust resistance genes using STS and SCAR markers, 83 Iranian wheat genotypes, Lr near-isogenic lines in Thatcher (positive controls), and the cultivar Thatcher (negative control) were used. After growing plants in the greenhouse, DNA was extracted by SDS method. Following that, polymerse chain reaction was performed for the markers of the resistance genes Lr9, Lr26, Lr28, Lr34, and Lr35 which amplified 1,100, 1,100, 378, 150, and 900 bp bands, respectively. Based on the results, the resistance genes Lr9 and Lr35 were only present in the positive controls. The resistance gene Lr26 was only detected in four cultivars; Arta, Pishtaz, Shiroodi, and Falat, and the gene Lr34 was present in six cultivars (Akbari, Bam, Tajan, Khazar 1, Sistan and Niknezhad). The Lr28 primer amplified a band of the same size in all genotypes even the negative control and therefore the presence/absence of this gene could not be validated. These results indicate the necessity for designing a specific primer for Lr28. In general, only the genes Lr26 and Lr34 were present in some genotypes. The genes Lr9 and Lr35 were not present in this collection and as based on rust surveys, no virulence has been detected for Lr9 and Lr28, so they could be transferred to suitable lines from donor sources.     

The successful experimental induction of necrotic enteritis in chickens by Clostridium perfringens: a critical review

Necrotic enteritis (NE) is one of the most important enteric diseases in poultry and is a high cost to the industry worldwide. It is caused by avian-specific, Necrotic Enteritis Beta toxin (NetB)-producing, strains of Clostridium perfringens that also possess in common other virulence-associated genes. In Europe the disease incidence has increased since the ban on in-feed “growth promoting” antibiotics. Because of this, many recent studies of NE have focused on finding different ways to control the disease, and on understanding its pathogenesis. Frustratingly, reproduction of the disease has proven impossible for some researchers. This review describes and discusses factors known to be important in reproducing the disease experimentally, as well as other considerations in reproducing the disease. The critical bacterial factor is the use of virulent, netB-positive, strains; virulence can be enhanced by using tpeL- positive strains and by the use of young rather than old broth cultures to increase toxin expression. Intestinal damaging factors, notably the use of concurrent or preceding coccidial infection, or administration of coccidial vaccines, combined with netB-positive C. perfringens administration, can also be used to induce NE. Nutritional factors, particularly feeding high percentage of cereals containing non-starch polysaccharides (NSP) (wheat, rye, and barley) enhance disease by increasing digesta viscosity, mucus production and bacterial growth. Animal proteins, especially fish meal, enhance C. perfringens proliferation and toxin production. Other factors are discussed that may affect outcome but for which evidence of their importance is lacking. The review compares the different challenge approaches; depending on the aim of particular studies, the different critical factors can be adjusted to affect the severity of the lesions induced. A standardized scoring system is proposed for international adoption based on gross rather than histopathological lesions; if universally adopted this will allow better comparison between studies done by different researchers. Also a scoring system is provided to assist decisions on humane euthanasia of sick birds.     

Prevalence and molecular characterization of bovine Cryptosporidium in Qazvin province, Iran

The aim of this study was to determine the prevalence, variability with host age, and the genotypes of species of Cryptosporidium in cattle from 15 dairy farms in Qazvin province, Iran. Fecal samples, collected from 272 cattle during May 2006 to December 2007, were characterized microscopically. Oocysts from 51 positive samples were analyzed using PCR assay of 18S SSU rRNA, restriction fragment length polymorphism (RFLP) and sequencing. We identified 72.6% of the positive samples as Cryptosporidium parvum, 17.7% as Cryptosporidium andersoni, 7.8% as Cryptosporidium bovis and 1.9% as a novel genotype of C. parvum possessing a single mutation on MboII restriction. An infection rate of 19.5% of C. parvum among 174 pre-weaned calves was significantly higher than the 3.1% among 98 post-weaned calves (P < 0.0006). This is the first report of C. bovis and the new subgenotype of C. parvum in Iranian cattle.