Amount Of Residual Protein Research Articles

Разработка метода оценки структурной гетерогенности популяции разных штаммов вируса клещевого энцефалита

Вирус клещевого энцефалита (ВКЭ) является возбудителем тяжелого неврологического заболевания человека и широко распространен на территории Евразии. При репродукции флавивирусов помимо инфекционных вирионов накапливается набор неинфекционных вирусных структур: незрелые формы вирионов, пустые формы (не содержащие геном вирусные частицы), а также агрегаты поверхностного белка Е, способные оказывать влияние на иммунный ответ, и патогенез. Штаммы ВКЭ могут различаться по соотношению этих форм в инфекционном материале, т.е. по характеру структурной гетерогенности. Цель: подобрать комплекс методов, способных выявить данные различия. Методы. Общую концентрацию белка Е определяли методом ИФА, число частиц, содержащих геном (ГСЧ) - ПЦР в реальном времени, а для выявления инфекционных вирусных частиц - титрование в культуре клеток. Результаты. Разработан метод оценки структурной гетерогенности популяции ВКЭ. Было показано, что повышенное содержание неинфекционных вирусных частиц, содержащих геном, и несвязанных с ними белка Е не зависит от подтипа вируса. Выводы. Штаммы ВКЭ отличились по соотношению общего числа ГСЧ к числу инфекционных вирионов и по содержанию белка Е, связанного и несвязанного с ГСЧ. Tick-borne encephalitis virus (TBEV) is widespread in Europe and Asia and causes severe neurological disease in humans. It has been established that the reproduction of flaviviruses leads to the accumulation of a whole set of non-infectious viral structures aside from infectious virions. These structures include immature virions, empty forms (containing no genome) and aggregates of the surface protein E. These structures, despite being non-infectious, are able to influence the immune response and, consequently, the pathogenesis of TBEV infection. The aim of this work was to select a set of methods which can be implemented to identify these differences. Methods. Virus samples were analised for protein E concentration, number of genome-containing particles and infectivity. The total concentration of protein E in samples was evaluated using ELISA. The number of genome-containing particles was determined by a real-time PCR, and to assess the number of infectious virus particles titration in PEK cell culture was used. Results. An assay for total concentration of protein E in culture fluid of cells infected with different strains of TBEV based on the commertially available ELISA kit was developed. TBEV strains used in the study varied by the ratio of genome-containing particles to infectious virions. The amount of protein E not associated with genome-containing virions was calculated as a difference between total content of protein E and the amount of protein E bound to genome-containing particles. This amount was also different for studied samples of TBEV strains. Conclusion. No correlation was observed between the increased content of non-infectious genome-containing particles or the amount of residual protein E and TBEV subtypes.

Re-evaluation of soybean hemicellulose (E426) as a food additive.

Following a request from the European Commission, the EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) was asked to deliver a scientific opinion on the re‐evaluation of soybean hemicellulose (E 426) as a food additive. Soybean hemicellulose is not absorbed intact, but is extensively fermented by the intestinal microflora in animals and humans. No adverse effects were reported in a 90‐day dietary toxicity study in rats at the highest doses tested of 2,430 mg/kg body weight (bw) per day for males and 2,910 mg/kg bw per day for females. Furthermore, soybean hemicellulose is not of genotoxic concern. The highest exposure estimates calculated based on the maximum permitted levels were up to 191 mg/kg bw per day for children (95th percentile). Given the limited uses, if any, reported, the Panel considered it probable that the actual dietary exposure to soybean hemicellulose (E 426) would be negligible. Following the conceptual framework for the risk assessment of certain food additives, the Panel concluded that it is very unlikely that there is a safety concern from the current use of soybean hemicellulose (E 426) as a food additive, and that there is no need for a numerical acceptable daily intake (ADI). The Panel recommended that the amount of residual proteins in E 426 should be reduced as much as possible, and that consumers should be informed of the presence of potentially allergenic proteins in the food additive.

Behaviors of particle size and bound proteins of oil bodies in soymilk processing

In unheated soymilk, extrinsic proteins are bound to intact oil bodies coated by one monolayer of phospholipids and oil body intrinsic oleosins. In this study, effects of heating (70–100°C; 0–30min) on particle size and bound proteins of oil bodies were examined in suspension (oil bodies from unheated soymilk into deionized water) and soymilk. Mass ratio of extrinsic proteins/oleosins of oil bodies in unheated suspension and soymilk was respectively 1.1 and 2.5. By heating, extrinsic proteins released from oil bodies with different rates, and Z-average size of oil bodies increased in the beginning; afterwards, residual extrinsic proteins (extrinsic proteins/oleosins: 0.31 in suspension and 0.74 in soymilk; 100°C, 4min) and Z-average size were affected little. The amount of residual proteins at 80–100°C was negatively correlated with Z-average size of oil bodies in suspension (R2=0.996) and soymilk (R2=0.890).

Antifungal effect of chitosan on the growth of Aspergillus parasiticus and production of aflatoxin B1

AbstractContamination of agricultural products by toxigenic fungi and the presence of mycotoxins cause serious economic damage, and toxic effects to humans and animals. In this study the effect of chitosan as a natural alternative for the control of the fungus Aspergillus parasiticus was evaluated. Chitosans were obtained from chitin previously extracted from shrimp heads using chemical (CS) and biological (CB) processes. The chitosan yields were 5.74 and 6.20% for CS and CB methods, respectively, with an amount of residual protein and ash below 1%, low molecular weight and degree of deacetylation of 80–82%. Chitosan showed fungistatic activity against A. parasiticus, with 6.71 and 10.66 g L−1 (CI50) of CS and CB, respectively, being required to delay fungal growth by 50% at 122 h. Chitosan (CI50) inhibited both radial growth up to 122 h, and germination of spores before 8 h higher than 50%. Chitosan also increased the average diameter of the spores and hyphae (P ≤ 0.05), reduced the septation process and increased the number of mitotic divisions of spores during germination. However, compared with control, chitosan decreased (P ≤ 0.05) aflatoxin B1 production at 8 days but increased (P ≤ 0.05) the total aflatoxins production by A. parasiticus. Copyright © 2011 Society of Chemical Industry

Possible synergistic effect between high lactate and insufficient intake of peptides caused biomass reduction during high-cell starter culture production

Lactic starter culture production is normally subjected to the end-product inhibition on growth, which limits the biomass produced per production batch. Removal of lactate ions during the biomass production has improved the biomass production. It allows for the use of higher sugar concentration so that high biomass concentration can be obtained. Lactate removal by ion exchange resin during Lactococcus lactis NZ133 cultivation was applied as a strategy for enhancing the production of lactic starter culture biomass. At high lactose concentrations of 180 g/l, the unexpected reduction in the biomass was evident regardless of the remaining sugar in the fermentation broth. The amount of protein and proteins/polypeptides pattern profile during cultivation were investigated as protein availability was suspected to be the potential cause of biomass reduction during high cell cultivation applying the ion exchange technique. Reduction in biomass concentration, after its maximum of 26 g/l, was observed after the protein concentration was unchanged while the remaining lactose continued to be utilised. A sharp decrease in protein concentration following the addition of resin corresponded to the disappearance of the smear band of protein sized 6,512-26,625 Da when more resin was added to remove lactate. The smear band remained throughout the conventional batch cultivation period. Based on the results, insufficient supply of peptides caused by the loss through adsorption onto ion exchange resin which occurred at high lactate level was postulated as the most probable cause of the biomass reduction. The result also indicated an inefficient use of supplemented protein sources supplied in correspond to the increase in lactose concentration due to the presence of appreciable amounts of residual protein at the end of cultivation process.

Application of High‐Intensity Ultrasound and Surfactants in Rice Starch Isolation

ABSTRACTHigh‐intensity ultrasound was evaluated as an alternative method to isolate rice starch without the use of chemicals as in the traditional alkaline steeping method. Surfactants, including sodium dodecyl sulfate (SDS), sodium stearoyl lactylate (SSL), and Tween 80, at 0.1, 0.3, or 0.5% combined with high‐intensity ultrasound were also investigated for rice starch isolation. A rice flour slurry (33%) was subjected to sonication for 15, 30, or 60 min at an amplitude of 25, 50, or 75% and at 40 or 50°C. The starch yield was not significantly affected by the treatment temperature and ranged from 46.7 to 76.2% (starch dry basis) after the sonication treatment; the protein and damaged starch contents of the isolated starches were 0.9–1.7% and 3.1–3.5% (dry basis), respectively. The combination of 0.5% SDS and high‐intensity ultrasound improved the starch yield to 84.9% with low residual protein, however, little improvement was observed with SSL or Tween 80. The pasting properties of isolated starch as measured by a Rapid Visco‐Analyser were affected by the treatment temperature and by the amount of residual protein and damaged starch. The thermal properties of the isolated starch were not changed by sonication and the amylose content remained unchanged. The surface of the isolated starch was not damaged by sonication as shown by scanning electron microscopy. High‐intensity ultrasound, alone or combined with SDS, showed a great potential for rice starch isolation in a short period of time without generating alkaline effluent.

Mutational diversity and hot spots in the alpha-sarcoglycan gene in autosomal recessive muscular dystrophy (LGMD2D).

Sarcoglycanopathies are a genetically heterogeneous group of autosomal recessive muscular dystrophies in which the primary defect may reside in any of the genes coding for the different partners of the...

Comparative studies of the Osborne protein fraction of wheat varieties with different dough and baking properties

The proteins of flours from the wheat varieties Clement (CLE) and Disponent (DIS), which are characterized by substitution of the wheat chromosome 1B by the rye chromosome 1R (CLE) and by 1BL/1RS-translocation of chromosome segments (DIS), respectively, and which yield sticky doughs, were extracted by the Osborne procedure and compared with the good variety Kolibri (KOL). CLE and DIS delivered significantly higher amounts of water-soluble proteins (31.2 and 23.2% of the total protein) than KOL (15.5%). The proportions of ethanol-soluble proteins were approximately constant for the three varieties (31.5-33.9%) while the amounts of residual proteins after extraction with ethanol were significantly different (CLE, 16.8%; DIS, 21.6%; KOL, 26.4%). Water extracts as well as residues exhibited also marked differences in their amino acid compositions. Investigation of the water extract from DIS by gel permeation chromatography and by RP-HPLC showed the presence of prolamins: omega 1,2-gliadins and/or omega-secalins could be detected on the basis of amino acid composition and N-terminal amino acid sequence. In the case of good varieties such as KOL, these prolamins seem to remain partially in the residue of the ethanol extract under the conditions of the classical Osborne procedure, whereas they are found in the water extract in the case of such varieties as CLE and DIS. On the other hand, a modified Osborne procedure (salt/ethanol/acetic acid) delivered the prolamins, which correspond to 39-40% of the total protein, completely within the ethanol fraction in the case of all three varieties.(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of the Removal of Sebum Soil from Cotton Undershirts in Japanese Home Laundry

To determine the most troublesome aspect of Japanese home laundry, a fact-finding survey and a series of uncontrolled wear-and-wash tests were carried out at 69 households selected at random throughout Japan. Of clothes washed during the period of the survey, 71 % were 100 % cotton fabrics and 14 %, cotton-synthetic blends. 1.6 kg of the clothing was washed in detergent solution having 57.1 ppm water hardness as CaCO3 at ambient temperature. The average number of wear-and-wash cycles was from 13.9 to 14.7 over a period of 40 days, depending on the type of clothing.Cotton undershirts use in the test were washed as mentioned above, using a spray-dried powdery heavy duty detergent containing no enzymes or special additives. By measuring the amounts of residual soil in cotton undershirts from 25 households, 27.4 mg of sebum/g of cloth and 3.3 mg of protein/g of cloth on the average were obtained from the shirts prior to the final washing at the end of an average of 14.7 wear-and-wash cycles of home laundry. The undershirts after the final washing contained 17.0 mg of sebum/g of cloth and 0.9 mg of protein/g of cloth on the average. Prior to and after the final washing, the amounts of residual sebum in cotton undershirts were more closely related to the number of wear-and-wash cycles than the amounts of residual protein. With increase in accumulated sebum, b values of cotton undershirts also increased. The amount of residual protein on clothing was not correlate to the b values of the clothing to the same extent as was the amount of residual sebum. Cotton undershirts soiled by sebum is thus shown to be one of the most difficult aspects of Japanese home laundry.

Negative Interference by Residual Proteins in the Supernatant Fluid Used in Radioisotopic Assay of Serum Vitamin B12

Abstract Separation of vitamin B12, from serum by heat denaturation results in an individually variable amount of residual protein in the supernatant fluid. I show that during radioisotopic assay of serum vitamin B12, such protein may seriously interfere with the results, and that the interference may be abolished by changing the experimental conditions.

THE INFLUENCE OF GROWTH MEDIA ON PROTEINS BOUND TO DNA AND THEIR POSSIBLE ROLE IN THE RESPONSE OF ESCHERICHIA COLI B TO ULTRAVIOLET LIGHT

The deoxyribonucleic acid (DNA) from cells of Escherichia coli B, after rigorous extraction, was found to contain residual amounts of protein, the quantity of which was determined by the medium in which the cells were grown. The DNA of cells grown in a minimal salts medium contained from 10 to 15 times more protein than the DNA of cells grown in an enriched medium. The addition of amino acids, vitamins, or nucleic acid bases to the growth medium resulted in a decrease in the amount of residual protein and an increase in the sensitivity of the cells to ultraviolet light. Of the enrichments tested, the amino acids produced the greatest decrease in the quantity of residual proteins and the largest increase in sensitivity to ultraviolet. The type of mutant cell produced by ultraviolet irradiation was found to be strongly influenced by the ingredients of the growth medium. Few mutants were found after the irradiation of cells grown in the minimal salts medium but when the growth medium was enriched with amino acids, many mutants requiring amino acids appeared. Similarly the addition of vitamins or bases resulted in the production of vitamin-and base-requiring mutants. It is suggested that these residual proteins become attached to specific sites on the DNA during the operation of certain genes and this results in an increase in the ability of the DNA to withstand the damaging action of desiccation and ultraviolet light.