RESUMEN
The combination of data obtained from isothermal mixing calorimetry and light scattering allowed us to reveal the relationships between the character of the interactions of casein (ß-casein and sodium caseinate (SCN) particles) with phosphatidylcholine (PC) liposomes and their specific properties, such as, the hydrophilic-lipophilic balance of the surface properties, the size, and the architecture. The size distribution diagrams, obtained by dynamic light scattering for the particles of pure PC, ß-casein and their complexes, indicated the involvement of both the protein and liposome particles in the complex formation at pH 5.5 and low ionic strength (0.001 M). As this took place, the data of the extraction of the free PC from the aqueous solutions of the complex particles by diethyl ether showed about 90% of the binding of the PC liposomes by the ß-casein particles. As a result of the interactions, the complex particles showed markedly higher values of their density, calculated on the basis of the light scattering data, as compared to the ones, which were inherent to the pure protein particles. The generality of the importance of such a structural parameter as the density of the complex (protein + PC) particles for their function as protectors against oxidation for the unsaturated PC was supported by the data obtained for the complex particles formed between SCN and PC liposomes at pH 5.5, 40 °C and the low ionic strength (0.001 M). In addition, the importance of both the density and the architecture of the complex (protein + PC) particles for their susceptibility to the proteolysis in the gastrointestinal tract was illustrated by the example of the proteolysis of the complex (ß-casein + PC) particles in the simulated gastrointestinal conditions in vitro.
Asunto(s)
Caseínas/química , Liposomas/química , Vehículos Farmacéuticos/química , Concentración Osmolar , Fosfatidilcolinas/química , Polímeros/química , Solubilidad , Propiedades de Superficie , TermodinámicaRESUMEN
The sodium caseinate (SCN)-maltodextrin (MD) covalent conjugates were prepared by a food-grade process involving the first step of the Maillard reaction. The covalent conjugates were prepared with different weight ratios of biopolymers (R(MD : SCN) = 0.4; 1; 2; 5) in the system using maltodextrins of strongly different dextrose equivalents (DE), i.e., DE = 2 and 10. We have observed that the covalent conjugation of SCN with MD, in contrast to their simple mixing, improved the protein solubility in an aqueous medium in a wide pH range that was more pronounced in the vicinity of the SCN isoelectric point (pH 3.8-4.4). The extent of SCN solubility was mainly governed by the weight/molar ratio of the biopolymers in the covalent conjugates, R(MD : SCN). Data of static multiangle laser light scattering showed that the revealed increase in the solubility of the conjugates could be predominantly attributable to the dramatic increase in their thermodynamic affinity for an aqueous medium. Which was most pronounced for the maltodextrin with the higher DE (DE = 10). The direct relationship between the increase in the solubility of the conjugates and the increase in their foaming ability, as compared against SCN, has been revealed as a rule both at neutral pH and at the pI. In addition, the found improvement in the protein foaming ability was also defined by both the weight/molar ratio (R(MD : SCN)) and the dextrose equivalent of the maltodextrins attached to the protein.
Asunto(s)
Caseínas/química , Polisacáridos/química , Concentración de Iones de Hidrógeno , Cinética , Estructura Molecular , TermodinámicaRESUMEN
Primary effusion lymphoma is a rare tumor of B-cell derivation which is associated with human herpes virus type 8 (HHV-8) in 100% and with human immunodeficiency virus (HIV) in most of cases. The paper describes the first case in Russia of HIV(-) HHV-8(+) Epstein-Barr virus (EBV)(+) primary effusion lymphoma in a male patient aged 56 years. The tumor was located in the pleural cavity. Interestingly, the patient was HIV-negative while having a positive tumor HHV-8 test. There are only 22 similar cases described worldwide.
Asunto(s)
Infecciones por Herpesviridae/virología , Herpesvirus Humano 8/aislamiento & purificación , Linfoma/virología , Anticuerpos Antivirales/sangre , ADN Viral/análisis , ADN Viral/genética , VIH/aislamiento & purificación , Herpesvirus Humano 4/aislamiento & purificación , Humanos , Masculino , Persona de Mediana Edad , Moscú , Cavidad Pleural/patologíaRESUMEN
Results of a first successful application of a direct photo-induced affinity modification of Tet repressor (TetR(D)) protein with tetracycline within a complex of known three-dimensional structure are described. The conditions of the modification have provided suitable yields of the modified complex and allowed characterization of the modified segments of the protein. The potential of tetracycline as a fine modifying reagent was established. In the complex of TetR(D) protein with tetracycline, the antibiotic modifies at least two segments, Ile59-Glu73 and Ala173-Glu183, which form a binding tunnel for the drug according to the X-ray analysis. These data open possibilities for the use of different tetracycline targets for structural studies in solution.
Asunto(s)
Proteínas Represoras/química , Tetraciclina/química , Secuencia de Aminoácidos , Datos de Secuencia Molecular , Etiquetas de Fotoafinidad , Difracción de Rayos XRESUMEN
By means of a developed method of histotopographical sections cartograms, 146 preparations obtained from female persons at the age of 8-25 years have been studied. The organ is intensively developing not only at 12-16 years of age, but at 22-25 years, as well. A close correlation is noted at 10-11 years of age between the mammary gland mass and the degree of its parenchyma (glandular tree) development. Subsequently, the connection between these indices becomes essentially weaker. At the age of 15-25 years, according to the variability and standard deviation quantile classes reflecting stages in the organ formation (the degree of the glandular tree development), five types of the mammary gland are distinguished: weak, low middle, middle, high middle and high. During transition of the mammary gland from the weak to the high type, at first the glandular tree is intensively developing in the periphery and in the internal parts, and then in the external squares and in the center of the organ. The degree of uneven development in the glandular tree increases when the middle type is reached. Subsequently, it decreases up to the initial level.