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Proper solubilization after precipitation and keeping the purified proteins in solution during the whole separation process are very critical to achieve accurate and high resolution patterns in two-dimensional gel electrophoresis (2-DE). Chaotropes and detergents are embedded in the sample and rehydration buffers in order to prevent hydrophobic interactions between the hydrophobic protein domains and avoid loss of proteins due to aggregation and precipitation. Unfortunately, detergents used for IEF must bear no net electrical charge and only week nonionic and zwitterionic detergents may be used in this process. Because of the low solubility of proteins at or very close to their isoelectric point, it seems that choice of chaotropes and detergents can dramatically affect on2D separations, especially in the case of very hydrophobic proteomes. Considering the physico-chemical heterogeneity of tear film protein content, it is deemed that solubilization can play an important role in 2D tear proteome analysis. So herein, we investigated the effect of some various detergents and chaotropes on the solubility of tear proteome during the sample preparation and IEF process. The results illustrated a very poor performance of non-ionic detergents (Triton­X-100 and Tween­80). Zwitterionic detergents (CHAPS and SB­3-10) had a better solubilization power and provided more reliable 2D maps. Last of all a great improvement in spot number and 2D resolution is achieved using a combination of urea/Thiourea in rehydration buffer and application of SDS in the sample buffer with a modified protocol, which ensures complete removal of anionic detergent during the first step of IEF and its replacement with the zwitterionic CHAPS.  

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Aims: The functional properties of proteins extracted by Isoelectric Solubilization/Precipitation (ISP) method are influenced by various factors such as the use of acid or base while protein extraction. The aim of this study was to investigate the functional properties of protein extracted from Crucian carp (Carassius carassius), using acidic and basic ISP method.
Materials & Methods: This experimental study was carried out on 56 Crucian carps in Bandar Torkaman City, Iran. The minced meat of fish was randomly divided to 2 homogeneous groups for implementing acidic and basic ISP method. The protein was isolated from meat and its functional properties were evaluated. The data were analyzed by SPSS 21 software, using two-sample t-test.
Findings: The protein extracted from Crucian carp meat had a significant difference in acidic and basic treatments (p<0.05). There was no difference in water holding between two treatments (p>0.05). The emulsion capacity of the extracted protein was significantly higher in basic treatment than the acidic treatment (p<0.05). The emulsion stability index was also significantly higher in basic treatment than acidic treatment. All samples had a flow behavior index (n) less than 1, indicating that these samples had a pseudoplastic behavior.
Conclusion: The protein extracted from Crucian carp meat is higher in the acidic treatment, but the basic treatment has better functional properties. The basic treatment has a higher emulsion capacity than the acidic treatment, and the stability index is high in the basic treatment. Protein solutions as well as acidic and basic emulsions have a pseudoplastic property. The amount of food viscosity is higher in acidic treatments compared to the basic treatment.

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The eukaryotic genome contains several replication Origins. Studies showed that the phenomenon and order of the origin activation is in a a particular discipline, called the “Replication Timing". Recent studies show that many factors are involved in regulating the timing of the replication process. One of the most important factors amongst them is the Rap1 interacting Factor 1 (Rif1) protein, which plays a key role in regulating the replication schedule in yeast and more advanced eukaryotes. Structure of this protein is mostly irregular and these properties prevent Rif1 from being expressed in a stable manner and makes it difficult to study.
The aim of the present study was to investigate the expression of recombinant C-terminal domain of mouse-Rif1(muRif1-CTD) protein in solution. For this purpose, the muRif1-CTD gene was extracted from eukaryotic constructs containing the complete Rif1 gene by PCR and was inserted into the pPAL7 expression vector comprising the Profinity eXact tag. Protein solubilization was carried out using different detergents and then detergent removal was performed by dialysis. In order to ensure that the soluble protein is active, the interaction analysis of the Rif1 protein with the G4 structures (previously reported to bind Rif1) was investigated using the gel shift assay. The results of this study showed the use of detergent for Rif1 solubilization without affecting its purification steps. But in the case of this protein, if the detergent is removed completely, it will not remain soluble.
 
 
 
 

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In recent decades, the aquaculture industry has experienced a growing trend. In this regard, rainbow trout (Oncorhynchus mykiss) is known as one of the most popular species in the world and in Iran, with Iran ranking first in the production of this fish with an annual production of about 237,710 tons. After processing this fish, about 30% of it is considered as processing residue, which includes head, bone, viscera, etc. In the present study, a mixture of minced head and backbone waste from this fish was used to extract glycosaminoglycan using the alkaline dissolution method. The results showed that the extraction yield, carbohydrate, sulfate, uronic acid and protein content of the extracted glucosamine-glycan sample were 1.96 ± 0.14, 59.67 ± 3.66, 10.19 ± 0.38, 7.76 ± 0.20 and 11.23 ± 1.43%, respectively. Additionally, the infrared spectroscopy (FTIR) analysis of the obtained sample indicated the presence of broad peaks in the range of 3200 to 3600 cm^-1 and 2700 to 3000 cm^-1, corresponding to the functional groups –OH and the stretching band C-H, and the bending band of sulfate S=O at 1245 cm ^-1. Furthermore, the stretching band of the functional group COO-, related to the presence of uronic acid in the extracted sample, was observed in the range of 1480 to 1640 cm ^-1. The peaks appearing at 1385 and 11450 cm ^-1 were related to the stretching band O-C=O and the stretching vibration –CO in the COOH group. 

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The aim of this study was to investigate the effect of steam treatment on nutritive value of date (Phoenix dactylifera) leaves. Date leaves were chopped and mixed with water or sulfuric acid solution to contain 50% moisture with or without 1% sulfuric acid. Steam treatment of the date leaves was carried out using three levels of steam pressure (14, 17 and 20 bar), three reaction times (120, 180, and 240 seconds) and two levels of acid (0 and 1 percent). The treated samples were analyzed for chemical composition including: cell wall components, ash, total extractable phenolics, water soluble sugars, and reducing sugars. Dry matter loss (DML), enzymic hydrolysis, and in vitro gas production of the samples were also measured. Results showed that steam treatment significantly affected (P< 0.05) cell wall components. An increasing trend was observed in DML by increasing harshness of treatment conditions. The lowest DML (12.7 g kg^-1) was observed in the auto-hydrolyzed (steam treatment without addition of exogenous acid) sample treated at 14 bar pressure and 120 seconds reaction time and the highest DML (78.8 g kg^-1) was observed in the acid-hydrolyzed (addition of 10 g kg^-1acid prior to treatment) samples treated at 20 bar pressure and 180 and 240 seconds reaction times. Steam treatment significantly (P< 0.05) decreased neutral detergent fiber (NDF) content but increased acid detergent lignin (ADL). Maximum changes in hemicellulose and water soluble sugars were observed in acid-hydrolyzed samples, in which hemicellulose decreased from 264.6 g kg^-1 in control to 72.2 g kg^-1 in the sample treated at 20 bar and 240 seconds and water soluble sugars increased from 14.0 g kg^-1 in the control to 101.8 g kg^-1 in the sample treated at 17 bar and 240 seconds. Enzymic hydrolysis of date leaves was improved after steam treatment and higher improvement was observed in acid-hydrolyzed samples. Gas production was significantly increased (P< 0.05) in all incubation times after steam treatment. The maximum increase in metabolizable energy (ME) estimated by gas production was from acid-hydrolyzed sample treated at 20 bar and 240 seconds. In auto-hydrolyzed samples, the biggest increase in ME was observed in the sample treated at 20 bar and 180 seconds. The results suggest that steam treatment could be used for upgrading the nutritive value of date leaves in the regions where date is grown and animals are encountered with severe feed shortage.