جستجوی مقالات مرتبط با کلیدواژه « لیزین » در نشریات گروه « زیست شناسی »

Biomimetic means imitating models, systems, and elements of nature to solve complex human problems. This field of science has led to the creation of new technologies inspired by biological solutions in macro and nano sizes. Thousands of people die every year due to diseases caused by antibiotic resistance. Therefore, the use of antimicrobial peptides has become particularly important.

in this study, branched polyethyleneimine polymer has been used as a biomimetic polymer of antibacterial peptides. In order to increase the antibacterial properties, the amino acids valine and lysine were used to modify the surface of branched polyethyleneimine. 1 H-NMR and FTIR were used to prove the binding of amino acids to the polymer. Antibacterial activity of the modified polymer by two methods of MIC test and growth inhibition zone on gram-positive bacteria S. aureus and B. subtilis and gram-negative bacteria E. coli and P. aeruginosa were examined.

Under optimal conditions, the concentration of branched polyethyleneimine polymer was 8 μl, and the amino acid valine to lysine ratio was 1: 6. Polyethyleneimine polymer modified with the amino acids valine and lysine inhibited bacterial growth concentration-dependent (p <0.05). 5 mg/ml of this polymer inhibits the growth of bacteria by more than 70%. The diameter of the inhibition zone of this polymer in examined bacteria reached about 15-20 mm. The antibacterial activity of this polymer was comparable to that of the antibiotic cefepime. It seems that this polymer can be used as an antibacterial polymer.

Since about 20% of the world's arable land and 50% of productions in the world are subject to salinity stress, it affects all stages of plant life from germination to seed production. The aim of this study was to investigate the effect of salinity stress on physiological and biochemical characteristics of some wheat cultivars. For this purpose, a factorial experiment was conducted in a completely randomized design with three replications. The first factor was salinity stress at three levels (control, 100 and 150 mM sodium chloride) and the second factor was wheat cultivars (Mihan, Heydari, Saisons and Gascogen). Plants were exposed to stress from two to four leaf stage and normal water was used for control treatment. Sampling was performed 14 days after stress application from treatet and the control samples. The results showed that among the studied cultivars, salinity stress decreased the concentration of chlorophyll a, chlorophyll b, carotenoids, total protein, and increased prolin, eantioxidant enzyme (peroxidase and polyphenol oxidase) activities and fresh weight of stems and leaves in Saison cultivar. Also, salinity stress did not have significant effect on the amino acids lysine and methionine. The activity of antioxidant enzymes is a very important defense mechanism and increasing the activity of peroxidase and polyphenol oxidase enzymes during salinity stress can reduce or prevent oxidative stress. In general, salinity affected wheat cultivars differently, because cultivars deal with salinity stress toxicity using different mechanisms.

Pseudomonas is considered as one of the most opportunistic and pathogenic microbes. Due to its high resistance to antibiotics, this bacterium has also encouraged the researchers to introduced alternative therapies, including phage therapy.

Recognition of the family of phages affecting the family of Pseudomonas and evaluation of the immunogenicity of antimicrobial lysine are considered here.

Here, the physio-chemical features of the family of phages affecting the bacterium Pseudomonas was investigated using bioinformatic and immunoinformatic databases. The secondary and tertiary structures of the lysines and the capacity of antigenicity in the host cells were determined.

The results showed that the three bacteriophage families Siphoviridae, Myoviridae, podoviridae with more than 90% abundance had the highest frequency among the bacteriophage families affecting Pseudomonas genus. Analyses of the lysine sequences of each of these three families showed immunity in only half of the total amino acids with a numerial value of half of the threshold of the software for B cells. 1% of amino acids had a strong affinity for MHC molecules those subjected to T cells. Total resulting:Due to the low induction of the immune response by phage lysine protein, they can be a candidate as alternative therapies for antibiotic resistance.

In order to investigate the response different of maize hybrids under drought stress in different levels growth stages, a field experiment was done as split plot layout based on randomized complete block design with three replications, in crop school of Meghan of Agriculture and natural Resources in year 2014. The treatments were included three irrigation regimes (Full irrigation, deficit irrigation at flowering and grain filling stage irrigation) in the main plots and seven commercial hybrids (single cross such as 260, 301, 302, 400, 500, 704 and 370 double-cross) the subplots assigned. Analysis of variance showed that the effect of drought stress levels, hybrids and interaction of drought stress level and hybrids were significant on protein content, carbohydrates, lysine, methionine, proline and activity of catalase, peroxidase and polyphenol oxidase. Grain yield was significantly influenced only by the main effect of stress and hybrids. The stress enhanced in most hybrids in protein, proline, carbohydrate and activity of catalase, peroxidase and polyphenol oxidase contents and reduction in the amount lysine and methionine contents. The highest enzyme activity and grain yield were observed in drought stress conditions of single cross 704 and the highest compatibility of metabolites were in stress of single cross hybrid 400 and 500. The highest grain yield of hybrid single cross 704 with an average 11.49 t/ha was obtained. The regression results also showed that in non-stress condition carbohydrates, highest contribution in predicting the yield and in stress conditions amount lysine and proline highest share of in determining yield to own devoted.

Lysine is an essential amino acid and has importance in food and pharmaceutical industry. Nowadays, there are different methods such as genetic and growth media optimization to enhance the lysine production. One of the useful methods in optimization of growth media is the response surface methodology.
In this study, lysine was produced by wild type of Corynebacterium glutamicum ATCC15032 and the production increased by response surface methodology. After selection of M9 culture media as a basic culture media, the effect of different factors such as carbon (glucose), nitrogen (ammonium sulphate) sources and methionine, as an additive, were studied on the lysine production. Then, the culture media and the time of incubation were optimized by response surface methodologyforlysine production.
The results showed that in M9 culture media, the amount of the produced lysine was 0.7 milligram per liter. In the optimized culture media (by response surface methodology) which has 14% glucose, 5% ammonium sulphate and 5mM methionine, lysine was produced up to 0.98 gram per liter after 2.5 days incubation. Pareto analysis indicated that methionine is the most effective factor in the lysine production. Finally, the results of granulation showed that the optimum condition for granulation of culture media (containing lysine) was achieved by adding starch, ammonium sulphate and sodium chloride in low pH and 100 °C.
Discussion and According to the results, the proposed culture media by response surface methodology causes 1400 times increase in the lysine production compared with M9 culture media and methionine had an important role in the production of lysine, probably by inhibiting the other metabolic pathway which has common metabolic precursor with lysine production metabolic pathway.

To study the effects of water stress on compatibility metabolites and the antioxidant enzyme activities of wheat variety trial a factorial experiment was conducted in a completely randomized design in 1393. The experiment consisted of three levels of stress (85, 60 and 35% of field capacity) and five varieties of wheat (Orom, Zarea, Mihan, ZSZOBKAYKA, JS3l7G217,) Analysis of variance showed, Proline, soluble sugars, lysine, methionine, protein and antioxidant enzyme activities of catalase, peroxidase and polyphenol oxidase and osmotic potential, the main and interaction effects of the drought were at 1%. Stress causes an increase in proline, soluble sugars, the activity of catalase, peroxidase and polyphenol oxidase and reduces the amount of lysine, methionine, protein and osmotic potential. The highest levels of proline, methionine, catalase, peroxidase, polyphenol oxidase from the figure of 35% was observed in tension Zarea. The highest sugar solution from the Orom, the highest lysine than ZSZOBKAYKA and highest protein content of 35% was obtained in tension at Mihan. It was also observed, the osmotic potential of the Mihan. Based on regression analysis osmotic potential under the influence of polyphenol oxidase activity and protein levels and Mihan with the highest level of protein and low PPO activity showed the highest potential osmotic stress.

This study was conducted to determine the effects of dietary supplementation of lysine and methionine on growth and nutrient utilization of Sobaity sea bream, Sparidentex hasta. Therefore, 180 juvenile fish with an initial weight of 31.38 ±1.4 g were distributed randomly among eighteen tanks. Fish were fed to satiation three time per day(08:00, 13:00 and 18:00 hours) for 8 weeks with formulated diets containing six different levels of dietary methionine and / or lysine;Diet 1: a control diet without dietary amino acid supplementation; Diet 2: 100% methionine supplementation; Diet 3: 75% methionine and 25% lysine supplementation; Diet 4: 50% methionine and 50% lysinesupplementation; Diet 5: 25% methionine and 75% lysine supplementation and Diet 6: 100% lysine supplementation. The results of this study showed that use of dietary lysine and methionine supplementation in diet, significantly affected (P.

Drought is one of the most important environmental stresses that adversely affect plant growth and crop production will In order to study a factorial randomized complete block design with three replications in greenhouse Ardabil University mohaghegh was conducted in 2013. Treatments were water stress at three levels: 35%, 55% and 75% field capacity and seed inoculated with mycorrhiza growth promoters (Glomus Mosseae), Rhizobium (Sinorhizobium meliloti), a mixture of both experienced and non-inoculated as results showed main effects and interaction between water stress and seed inoculation rates at 1% level of proline, soluble sugar, membrane stability, osmotic potential, plant height and leaf area was significantly influence of alfalfa, however lysine and methionine levels were changed only main effects. Increase the stiffness of proline, soluble sugar and decrease osmotic potential, membrane stability, lysine, stem height and leaf area were. Growth stimuli by increasing the production of metabolites and increased osmotic potential and membrane stability reduces the damaging effects of stress and increase plant height and leaf area were of alfalfa. Mycorrhiza and Rhizobium have performed better in most traits, but simultaneously they always showed the highest value. Also according to the regression equations in tension 85% proline and methionine had the highest share in the determination of cell water and the portion of the methionine reduces stress and enhances the contribution of soluble sugars and proline in determining the relative water content increases this increases the osmotic potential contribution in determining the relative water content in cells. Rhizobium and mycorrhiza mixture of proline and methionine, the highest share in determining the relative water content of the cells showed. Changes in leaf water content of a quadratic equation, but stem cells compared with less leaf area affected by the water content of cells Generally use a mixture of mycorrhiza and Rhizobium is always the best treatment for reducing stress have to show that there is a relationship between them Synvzhyst

Inroduction & A feeding trial was conducted to examine the effects of dietary supplementation of lysine and methionine on growthperformance and haemato-biochemical status in beluga, Huso huso. 240 fish with average weight of 144.6 ± 4.64 g were fed one of four the experimental soy protein based diets D0 (without lysine or methionine supplementation), D1 (lysine supplementation alone), D2 (methionine supplementation alone) and D3 (both lysine and methionine supplementation) were fed to triplicate groups for 12wk. L-Lysine and DL-methionine were added to the diets containing 344 g kg-1 soybean meals at 12.02 and 12.94 g kg-1 of dry diet respectively. Significant higher weight gain, specific growth rate, protein efficiency ratio, condition factor, feed efficiency ratio, haemoglobin concentration, white blood cell and total blood protein were observed in fish fed soya protein-based diet supplemented with both lysine and methionine than that of fish of other dietary groups. There were no significant differences among fish fed diet supplemented with either methionine or lysine. Growth performances, feed utilization and haemato-biochemical status of fish fed control diet was significantly lower than those of fish fed diet supplemented both lysine and methionine and supplemented with either methionine or lysine. The present study showed that soybeen meal could be included in the beluga diet up to 344 g kg1, to replace 40% of fishmeal supplemented both lysine and methionine without any adverce effect on the growth performances and feed utilization.

The­ purpose of this study to demonstrate the effects of lysine supplement on Small Intestine Morphometrics of broilers chickens. 180 day old male Ross breed broiler were purchased and divided into 3 groups. In starter period Control group received diet containing 1.2% lysine, Treatment 1 and Treatment 2 group received diet containing 1.3% and 1.4% Lysine, respectively. In Grower period Control group received diet containing 1.1% lysine, Treatment 1 and Treatment 2 group received diet containing 1.2% and 1.3% Lysine, respectively. Intestine villous Morphometrics examination was done by analyzing of villi's height, width and depth of crypts. PAS solution was used in order to staining samples. Data analyzed by SPSS 17software through one-way variance analysis and Tukey Test. The finding shown that as diet lysine increased, in trearment2 the villous height and crypt depth had a significant increase compared to the control Group. The growth of intestine villous width which depends on lysine density had significant increase (P<0.05) compared to control group. Lysine had no significant effect villous height to crypt depth ratio and villous height to villous width ratio in the jejunum.

Soybean (Glycine max (L.) Merr.) is a thermophilic plant. But the temperature up to 40°C inhibits its seed germination. In this research, the role of exogenous polyamines (putrescine, spermidine and spermine) in the heat-shock protection of soybean seedlings c.v Sahar was investigated. Also effects of pretreatment of polyamine inhibitor, on seedling growth were monitored. Results showed that exposure to heat-shock decreased growth whereas application of putrescine and spermidine increased thermo-tolerance and growth recovery. Similarly, lysine, an amino acid, was tested at equivalent concentration to demonstrate that heat- shock protection is really a polyamine phenomenon and not simply a growth effect from a source of nitrogen. The results showed that, polyamines did not act merely as a source of nitrogen when stimulating growth, suggesting stress adaptive role of polyamines. Pretreatment of polyamines plus biosynthetic inhibitors reduced the inhibitory effects and enhance growth recovery.