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The transgenic chicken has great potential as a bioreactor for the production of valuable pharmaceutical proteins, notably in the oviduct/egg. Whereas conventional transgenic approaches have significant limitations in this species, an alternative approach employing primordial germ cells (PGCs), the progenitor cells to ova and spermatozoa, has now been successfully applied to the insertion of exogenous genes into birds. Recent developments in manipulating avian embryos make it possible to produce germline chimeras derived from transferred PGCs. In this review we describe the migration pathway of chicken PGCs during early development. We then summarize different methods for the isolation of PGCs and the diversity of techniques used to introduce genes into these cells. Finally, we describe an in vitro assay for testing tissue-specific vectors designed to express heterologous proteins in transgenic chickens.
Lactoferrin (LF) is an iron-binding glycoprotein present in the cytoplasmic granules of neutrophils and in external secretions of mammals. Although the biological role of human and bovine lactoferrin has been extensively studied, there is still uncertainty as to the nature and function of lactoferrin receptors. We recently determined that methyl-α-D-mannopyranoside given intraperitoneally (i.p.) could suppress the adjuvant activity of LF in the generation of delayed-type hypersensitivity (DTH) to ovalbumin (OVA). We concluded that the lactoferrin effects in DTH are mediated by carbohydrate-recognizing receptors like the mannose receptor (MR). This study indicates that subcutaneous (s.c.) administration of very small doses of the Man-bovine serum albumin (Man-BSA) complex, together with a sensitizing dose of the antigen, gives the same effects as i.p. administration of methyl-α-D-mannopyranoside. The latter is also a blocker of MR, although of a much lower affinity to the receptor than Man-BSA. The blocking of the adjuvant effect of LF by the Man-BSA complex (when given together with the sensitising dose of antigen) suggests that the function of antigen-presenting cells in the skin (presumably immature dendritic cells expressing MR) is inhibited. The results of our study indicate that a receptor with an affinity for mannose is essential for the mediation of adjuvant lactoferrin function in the generation of DTH.
Stimulated neutrophils (PMNL) are a source of the active oxygen species: O2, H2O2 and HOCl/OCT which in turn can act on proteins yielding a variety of mixed oxidation products. A system is proposed in which a model protein — ovalbumin (OVA) first undergoes chlorination by HOC1/OCT and next is oxidised by H2O2. The modification of functional groups (-NH2, -SH, -S-S-, >C=0, Tyr and Trp) in OVA was monitored as well as their accessibility to promote aggregation. Chlorination resulted in additional inter- or intra -S-S- bond formation followed by a decrease in the total sulfhydryl group content. Amino groups were oxidised to carbonyl moieties with a concomitant acidic shift of pi. Formation of chlorotyrosine at the chlorination step was confirmed and its further H202-mediated transformation to bityrosine was demonstrated. It has also been confirmed that tryptophan, and not tyrosine, is the first target for chlorination. SDS/PAGE and HPLC profiles revealed that HOCiyOCl" chlorination promotes formation of aggregates stabilised by non covalent bonds. In conclusion, we suggest that a dramatic change in the OVA molecule structure begins when the molar excess of HOC1/OC1 is about 2 per one reactive group in OVA.
The objective of this study was to evaluate effectiveness of Ovalbumin-LHRH-7 (OL) protein when injected in crude, purified, free or encapsulated forms and using a single vaccination protocol along with CpG, inulin and saponin adjuvants. Fifty six C57BL/6 mice in seven groups (n=8) received various treatments and doses: Group 1 was control; Group 2 and 3 were injected twice with purified or crude OL protein, respectively, 4 wks apart. Group 4 and 5 were injected only once with purified or crude OL protein, respectively. Group 6 was injected only once with a mix of purified OL protein and encapsulated purified OL protein. Group 7 was injected only once with a mix of crude OL protein and encapsulated crude OL protein. There was an immunization effect observed on the I125 LHRH % binding (P<0.05). Antibodies (Abs) against LHRH were identified on week 5 of immunization in groups 2, 3 and 4. Boosting at week 5 caused a significant increase in LHRH antibody (Ab) concentrations in groups 2 and 3. Numbers of pregnant animals and prengnancy rates were suppressed in all treatment groups at various degrees (P<0.05). Numbers of pups born were affected by immunization (P<0.05).Concluding, immunization with OL protein generated either biological or both immunological and biological effects in the most of treatment groups. The study confirmed the earlier findings that purified OL protein with CpG adjuvant is effective in inducing immune response and suppressing reproductive functions. However, the original idea that the non-capsulated antigen/adjuvant mix would work as primary injection, while encapsulated counterpart would mimic booster injections in a single vaccination protocol could not be confirmed in this study. Further studies to determine affecting factors for single-injection LHRH immunization are needed.
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The antioxidant capacity as free radicals of 1,1 diphenyl-2-picryhydrazyl (DPPH) scavenger of egg white protein hydrolysate was investigated. Egg white protein precipitate obtained as a by-product in cystatin and lysozyme isolation was hydrolysed with bovine trypsin and then separated by means of RP-HPLC. Of ten fractions collected only no. 2 (0.195 μmol Trolox /mg) and no. 5 (0.186 μmol Trolox /mg) displayed a considerable free radicalscavenging capacity. The rechromatography of these fractions yielded four products of raised antioxidant activity: no. 2E (obtained from fraction no. 2) and no. 5E, 5F, 5H (obtained from fraction no. 5) which amounted to 0.482 μmol Trolox /mg and 0.584, 1.375, 1.200 μmol Trolox /mg, respectively.
Increasing the potency of antihypertensive food-derived peptides is a critical and important step in the development of natural drugs for cardiovascular diseases prevention. We have proposed the egg-white protein precipitate (EWPP) obtained as a byproduct of cystatin and lysozyme isolation as a potential source of ACE-inhibitory peptides derived by pepsin digestion. The results indicated that hydrolysis of EWPP with pepsin produced the ACE inhibitory activity. During 3-h hydrolysis (DH: 38.3%), the IC50 value of EWPP hydrolysate was signifi cantly increased and fi nally reached IC50=643.1 μg/mL. This hydrolysate was further fractionated by RP-HPLC. The peptide fraction exhibiting the highest ACE inhibitory activity was rechromatographed. Three peptide subfractions exhibiting ACE-inhibitory activities of 69.0, 25.0, and 37.6 μg/mL were further characterised. In each of them, mixtures of peptides with different molecular masses were observed.
Sulfatide (galactosylceramide I3 -sulfate) has been reported to activate blood coagulation factor XII (Hageman factor), which suggests that it exhibits coagulant activity (Fujikama et al., 1980 Biochemistry 19, 1322-1330) However, sulfatide administered into animals as a bolus shot without subsequent thrombus formation, prolonged conventional clotting times and bleeding time (Hara et al., 1996 Glycoconjugate J. 13, 187-194). These findings suggest that it may exhibit anticoagulant rather than coagulant activity. Following this suggestion we found in vitro that binding of sulfatide to fibrinogen resulted in disturbance of fibrin formation. To examine a possible pharmacological effect of sulfatide on blood coagulation in vivo we continuously infused sulfatide into rats through plastic cannulae and found formation of giant thrombi around the tips of the cannulae. These data suggest that sulfatide may exhibit contradictory functions in the blood coagulation system.
The aim of this study was to evaluate the influence of pretreatment with the phosphodiesterase-4 inhibitor rolipram on pulmonary resistance, influx of inflammatory cells, and histamine concentration in bronchoalveolar lavage fluid (BALF) during an experimental asthmatic reaction induced in ovalbumin (OA)-sensitized guinea pigs, challenged with OA inhalation. The experiment was performed in three groups of guinea pigs: two experimental groups, pretreated with rolipram or dexamethasone, and a control group without any pretreatment. Lung resistance (LR) was continuously recorded under suppression of spontaneous breathing during early asthmatic reaction. BALF was obtained before and at three time points up to 24 hr after the challenge. In the untreated, control animals a transient, significant increase in neutrophils, total and CD4+ lymphocytes, macrophages, eosinophils, and in histamine concentration in BALF was noted. Pretreatment with rolipram significantly reduced LR, eosinophils infiltration, and histamine release into the bronchoalveolar space during the early asthmatic reaction. These effects were generally comparable with those of dexamethasone, except that dexamethasone also reduced the influx of neutrophils into BALF.
Przedmiotem badań był preparat owoalbuminowy stanowiący produkt uboczny uzyskiwany podczas wydzielania lizozymu i cystatyny z białka jaja kurzego, które poddano hydrolizie enzymatycznej. Początkowo oceniono podatność tego białka na działanie handlo­wych preparatów proteinaz: termolizyny, pronazy i neutrazy oraz enzymów proteolitycznych pozyskanych z dyni figolistnej (Cucurbitaficifolia) oraz z drożdży Y. lipolytica: serynowej i aspartylowej proteinazy. Do dalszej hydrolizy wykorzystano trzy ostatnie enzymy. Rozkład białka śledzono podczas 24-godzinnej inkubacji enzymu z substratem, oznaczając stopień jego hydrolizy i przyrost wolnych grup aminowych, a także prowadząc rozdział chromato­graficzny metodą RP-HPLC. Stwierdzono, że najgłębszą degradację preparatu owoalbumi- nowego na poziomie 45% uzyskano pod wpływem proteinazy serynowej z dyni. Wyraźnie niższą aktywność wobec tego białka przejawiały obydwie proteinazy drożdżowe. Profile pep- tydowe RP-HPLC uzyskanych hydrolizatów potwierdziły różnice w podatności preparatu owoalbuminy na działanie testowanych enzymów proteolitycznych.
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