Background and objectives: Tragacanth gum (GT) is one of the natural secreted hydrocolloids which has many applications in food and pharmaceutical industries. Unfortunately, there is limited scientific information about the electrostatic interactions of tragacanth gum with proteins, especially the proteins unfolded by physical approaches. In this regard, the main objective of this study was to investigate the effect of thermal processing on the whey protein isolate (WPI) properties and its complexation with tragacanth gum. Materials and methods: The influence of heating time (0, 5, 10, 15, 20, 25, 30 and 35 min at 80 C) on the turbidity of WPI, alone and mixed with GT (r = 0. 1, pH 4. 0 and Cp 0. 1 w/w) was surveyed. Then, the flow behaviour and viscosity of GT-WPI mixture at a shear rate of 0-100 S-1 (pH 4. 0) was compared with the individual solutions of gum and protein. Since the maximum turbidity was observed in the range of 15-35° C, the impact of heating time at three levels (15, 25 and 35 min) and biopolymer mixing ratio at six levels (2: 1, 1: 1, 1: 2, 1: 5, 1: 10 and 1: 20) on the protein and carbohydrate compositions of precipitate and supernatant was investigated by Lowry and phenol-sulphuric acid methods, respectively. Results: Turbidity of protein solutions significantly changed with rising the heating time such that the maximum turbidity achieved after 25 min thermal processing. While these solutions were unstable due to protein-protein interaction and formation of protein aggregates, GT addition led to significant changes in the stability of protein solutions as a result of protein-polysaccharide interactions. Similar to protein solutions, the maximum turbidity of the complexes was achieved after 25min thermal processing. The rheological measurements showed that the mixture solution had pseudoplastic behavior with a large hysteresis loop as well as the higher viscosity rather than the blank solutions, indicating the formation of electrostatic interactions between protein and polysaccharide. By determining protein and polysaccharide content in the supernatant and precipitate phases, the least ratio of Pr: PS was observed for the 25-min heated WPI. Furthermore, the ratio of Pr: PS in the precipitate was increased significantly as Pr: PSratio was increased in the mixture. Conclusion: Addition of tragacanth gum to the whey protein isolate led to a significant stability in the solution. Due to unfolding of WPI, using thermal processing on the whey protein isloate solution resulted in a meaningful increase in the turbidity of protein solution and the efficiency of GT-WPI complex formation.

Basal stem rot caused by Sclerotinia sclerotiorum (Lib.) de Bary is one of the most important diseases of sunflower. Quantitative trait loci (QTL) implicated in partial resistance to two isolates of S. sclerotiorum (SSU107 and SSKH41) were investigated using F9 recombinant inbred lines (RILs) from the cross between sunflower parental lines PAC2 and RHA266. Experiments were conducted in completely randomized design with 3-6 replications under controlled conditions. The reaction of genotypes to basal stem rot disease was evaluated by measuring the percentage of necrosis area three days after inoculation. Combined analysis of experiments showed significant interactions between sunflower genotypes and S. sclerotiorum isolates suggesting that partial resistance to S. sclerotiorum should be isolate-specific in sunflower. QTLs were mapped using an updated high-density SSR and SNP linkage map. The map consisted of 210 SSRs and 11 genederived markers placed in 17 linkage groups (LGs). The total map length was 1,653.1 cM with a mean density of 1 marker per 7.44 cM. A total of 14 QTLs were detected for partial resistance to two isolates. The phenotypic variance explained by QTLs (R2) ranged from 0.10 to 9.85. The sign of additive gene effects showed that favorable alleles for partial resistance to isolates came from both parents. Six QTLs were common between two isolates on LGs 1, 8 and 17, whereas the others were specific for each isolate. Colocalized QTLs on LG 1 were linked to the glutathione S-transferase gene (GST). The colocalized QTLs for partial resistance to basal stem rot isolates could be good candidates for marker assisted selection (MAS).

Objective (s): In recent years, the biosynthesis of gold nanoparticles has been the focus of interest because of their emerging application in a number of areas such as biomedicine. In the present study we report the extracellular biosynthesis of gold nanoparticles (AuNPs) by using a positive bacterium named Streptomyces fulvissimus isolate U from rice fields of Guilan Province, Iran.Materials and Methods: From over 20 Streptomyces isolates collected, isolate U showed high AuNPs biosynthesis activity. To determine its taxonomical identity, its morphology was characterized by scanning electron microscope and partial molecular analysis performed by PCR. In this regard, 16S rDNA of isolate U was amplified using universal bacterial primers FD1 and RP2. The PCR products were purified and sequenced. Sequence analysis of 16S rDNA was then conducted using NCBI BLAST method. In biosynthesis of AuNPs by this bacterium, the biomass of bacterium exposed to the HAuCl4 solution.Results: The nanoparticles obtained were characterized by UV-Visible spectroscopy, transmission electron microscopy (TEM) and Energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction spectroscopy (XRD) analyses. Our results indicated that Streptomyces fulvissimus isolate U bio-synthesizes extracellular AuNPs in the range of 20-50 nm.Conclusions: This technique of green synthesis of AuNPs by a microbial source may become a promising method because of its environmental safety. Its optimization may make it a potential procedure for industrial production of gold nanoparticles.

Functional properties of total protein isolate (TPI) were investigated. The moisture content and ash content of the TPI was found to be 9.16% and 3.92% respectively. The nitrogen solubility of the protein isolate was found to be maximum at pH 7. The foaming capacity, emulsifying activity and emulsifying stability were greatly affected by pH levels.Viscosity of the TPI solution also changes with pH and increases increase in concentration.Gelation properties of the protein isolate solution were investigated and the lowest gelation concentration was found to be 10%. Water holding capacity of the protein isolate was 3.60 g water/g protein and the oil holding capacity was 2.02 g oil/g protein.

During the winter and spring of 2007 and 2008, 450 samples (leaves of carnation plants) showing symptoms of yellowing, mottling, leaf malformation, and stunting were collected from greenhouses in Mashhad and Chenaran regions. The samples were tested by DAS-ELISA for the presence of CarMV. Total RNA was extracted by RNXTM (-Plus) solution from positive infected samples confirmed in DAS-ELISA tests. AccuPowerR RT Pre Mix Kit was used for synthesis of cDNA with reverse specific primer according to two segments of genome. PCR amplification of cDNA was carried out using AccupowerR PCR PreMix. RT-PCR assay amplified two DNA fragments approximately 1037bp and 676 bp using. PCR products directly sequenced. The nucleotide sequence identity was also compared with different isolates of the world. The determined sequences of FUM2 isolate of CarMV were compared which previously reported 23 CarMV isolates, using Bioedit software and ClastalW2. A Neighbor-joining method of MEGA 3.1 was applied to construct unrooted trees for 3 genes (p7, p9 and partial p38). Analysis of the phylogenetic tree showed that our isolate is in group I and subgroup A.

Persian gum is an anionic polysaccharide, exudes from mountain almond tree. Unfortunately, there is no information about its interaction with unfolded proteins. The objectives of the current study are investigation of heating time on the properties of WPI and the complexes thereof. In this regard, first the effect of thermal processing (at 80°C, for 0-35 min) on the turbidity of whey protein isolate was surveyed at pH 4.0. The electrostatic interaction between treated WPI and Persian gum was also surveyed as a function of heating time and mixing ratios (2: 1, 1: 1, 1: 2, 1: 5, 1: 10 and 1: 20). Results indicated the significant increasing in the turbidity of treated WPI solutions (mainly after 25 min) with a high inconsistency leading to the precipitation due to the protein-protein interactions at low pH and formation of large aggregates. Addition of Persian gum (PG) caused the formation of WPI-PG complexes and meaningful increasing in the stability of the mixture solutions. Furthermore, the rheological measurements (0-100 S-1) showed that the mixture solution has pseudo plastic behavior with a large hysteresis loop and higher viscosity rather than the blank solutions, indicating the formation of protein polysaccharide complexes. By calculation of protein and polysaccharide in the supernatant and precipitation phases, the most biopolymer concentration in the precipitation phase was demonstrated for the 35-min-treated WPI. On the other hand, the amount of polysaccharide was increased in the precipitation as WPI: PG mixing ratio decreased.