Inhibition of benzoyl peroxide/Cu2+-dependent lipid peroxidation by manganese

1. Formation of peroxides by benxoyl peroxide (BPO) and CuCl2 was examined in the human red blood cell ghost. 2. Amounts of peroxides formed increased with the amount of the ghost solution added. 3. Of all the cations tested only manganese ion inhibited the formation of peroxides in BPO-CuCl2 reaction system. 4. The formation of peroxides was inhibited approx. 50% with 0.4 microM manganese. 5. The inhibitory manner of manganese was non-competitive against copper.     

Changes in the amino acid sequence of hemagglutinin during sequential adaptation of human influenza virus A to replication in mice

The primary structure of hemagglutinin (HA) gene of Influenza virus A/USSR/90/77 (H1N1) variants after 3 and 11 passages has been determined. In the HA1 coding region of mice-adapted virus (11 passages) there are two amino acid substitutions: Thr 89----Ala and Asn 127----Asp. At the first stage of adaptation (3-rd passage) only a single mutation was detected: Asn 127----Asp. The adaptation is accompanied by the loss of specific carbohydrate attachment sites adjacent to the receptor-binding site located at HA1 subunit with a concomitant variation in antigenicity.     

Thermal inhibition of repair of methylmethane sulfonate-damaged DNA in chick embryo fibroblasts

Chick embryo fibroblasts were treated with the monofunctional alkylating agent methylmethane sulfonate at various concentrations for 1 h at 42°C, rinsed and then incubated post-treatment at various temperatures at which the kinetics of alkali-labile bond disappearance was followed. Growth experiments showed that these cells grew similarly at temperatures of either 37°C or 42°C. Repair as assessed by removal of alkali-labile bond was also similar for postincubation in the temperature range 37–42°C for damage due to methylmethane sulfonate treatment at concentrations less than 1.5 mM. When the postincubation temperature was raised higher than 42.5–43°C, this type of repair was stopped. The normal internal body temperature of adult chickens is about 41.6°C. Hence the present finding indicates that chick cells are much more severely restricted in DNA repair at temperatures above normal than are mammalian cells, which can function in this respect for several deg. C above 37°C.     

Lymphocyte migration in internally irradiated animals. Effect of internal gamma radiation on the migration properties of spleen lymphocytes labeled with 51Cr

In experiments on CBA mice it was shown that migration of 51Cr-labeled spleen lymphocytes, injected intravenously, to lymph nodes of intact recipients was suppressed 6-24 months after the administration of a radiopharmaceutic preparation of selenium-75-selenomethionine in a quantity forming the doses of 1 Gy and 1.5 Gy absorbed within the whole body and lymphoid organs, respectively. Migration of labeled lymphocytes to the liver, kidneys and lungs, as well as their retention in the circulating blood, were increased. As the result of the migration disorders the specific affinity of lymphocytes for peripheral lymphoid tissue decreased.     

Bacterial reduction of hexavalent molybdenum to molybdenum blue

A bacterium that was able to tolerate and reduce as high as 50 mM of sodium molybdate to molybdenum blue has been isolated from a metal recycling ground. The isolate was tentatively identified as Serratia sp. strain Dr.Y8 based on the carbon utilization profiles using Biolog GN plates and partial 16S rDNA molecular phylogeny. ANOVA analysis showed that isolate Dr.Y8 produced significantly higher (P < 0.05) amount of Mo-blue with 3, 5.1 and 11.3 times more molybdenum blue than previously isolated molybdenum reducers such as Serratia marcescens strain Dr.Y6, E. coli K12 and E. cloacae strain 48, respectively. Its molybdate reduction characteristics were studied in this work. Electron donor sources such as sucrose, mannitol, fructose, glucose and starch supported molybdate reduction. The optimum phosphate, pH and temperature that supported molybdate reduction were 5 mM, pH 6.0 and 37°C, respectively. The molybdenum blue produced from cellular reduction exhibited a unique absorption spectrum with a maximum peak at 865 nm and a shoulder at 700 nm. Metal ions such as chromium, silver, copper and mercury resulted in approximately 61, 57, 80, and 69% inhibition of the molybdenum-reducing activity at 1 mM, respectively. The reduction characteristics of strain Dr.Y8 suggest that it would be useful in future molybdenum bioremediation.     

Habitat selection in rock pool corixids: the effect of local density on dispersal

The corixid species breeding in temporary rock pools of Baltic archipelago live in a highly fragmented and unpredictable habitat. Shallow rock pools can dry out and be refilled repeatedly during a summer causing high mortality of immatures. In deeper pools, young nymphs face intense competition by older stages including cannibalism. The adult corixids move frequently between rock pools and are thus able to use currently available habitat for reproduction. In this dispersal behaviour, the ability to assess the local population density and hence select the more suitable low density patches would be advantageous. We studied the effect of local population density on the frequency of dispersive flights of Arctocorisa carinata (Sahlberg) and Callicorixa producta (Reuter) experimentally, using rock pools from which nymphs of both species were removed. The dispersal rates of marked C. producta adults were significantly lower from experimental rock pools than from normal density controls, leading to a concentration of C. producta adults in the experimental rock pools. Indications of immigration rate differences between the experimental and control pools were also observed. No clear differences were found in the superior competitor A. carinata.     

Properties and uses of protein hydrolysates (Review)

Properties of protein hydrolysates and possible uses of these substances in research and various branches of industry are considered. The main problem discussed in this paper is the relationship between the degree of protein conversion and characteristics (structural-functional and physicochemical) of hydrolysates.     

The Effect of Academic Load and Work Conditions on the Sympathoadrenal Function and the Indices of Heart Rhythm Regulation in 17- to 18-Year-Old Girls

The dynamics of the sympathoadrenal function and the specific features of heart rhythm regulation were studied in female students and clothing factory female workers during their adaptation to academic and work conditions. Periods of the strongest functional tension in test systems were found in first-year students: the beginning of an academic year, the end of the first semester, and a period after winter examinations, all characterized by an increase in the central-circuit and sympathetic effects on sinus rhythm, acceleration of the heart rate, activation of sympathoadrenal mechanisms, and a decrease in sympathoadrenal reserves. The comparative analysis allowed us to disclose general trends typical of females of this age group such as the relative maturity of the sympathoadrenal system (SAS) and optimum correlation between autonomic and centralized heart rhythm regulation and to reveal the differences in the character and dynamics of functional shifts caused by a specific effect of academic load and work conditions. The degree of correlation between the indices characteristic of hormonal and mediator SAS mechanisms and the statistical characteristics of heart rhythm was proposed as the criteria for estimating the functional tension of the human body.     

Seasonal changes in the cecal microflora of the high-arctic Svalbard reindeer (Rangifer tarandus platyrhynchus)

The dominant cecal bacteria in the high-arctic Svalbard reindeer were characterized, their population densities were estimated, and cecal pH was determined in summer, when food quality and availability is good, and in winter, when it is very poor. In summer the total culturable viable bacterial population was (8.9 +/- 5.3) X 10(8) cells ml-1, whereas in winter it was (1.5 +/- 0.7) X 10(8) cells ml-1, representing a decrease to 17% of the summer population density. Of the dominant species of cultured bacteria, Butyrivibrio fibrisolvens represented 23% in summer and 18% in winter. Streptococcus bovis represented 17% in summer and 5% in winter. Bacteroides ruminicola represented 10% in summer and 26% in winter. In summer and winter, respectively, the proportion of the viable population showing the following activities was as follows: fiber digestion, 36 and 48%; cellulolysis, 10 and 6%; xylanolysis, 33 and 48%; and starch utilization, 77 and 71%. The most abundant cellulolytic species in summer was Butyrivibrio fibrisolvens, representing 62% of the total cellulolytic population, and in winter it was Ruminococcus albus, representing 80% of the total cellulolytic population. The most abundant xylanolytic species in summer was Butyrivibrio fibrisolvens, and in winter it was Bacteroides ruminicola, representing 59 and 54% of the xylanolytic isolates in summer and winter, respectively. The cecal bacterial of the Svalbard reindeer have the ability to digest starch and the major structural carbohydrates of the diet that are not digested in the rumen. The cecum in these animals has the potential to contribute very substantially to the digestion of the available plant material in both summer and winter.     

Calcium control of glycogen synthase activities in mouse diaphragms, rat adipocytes and rat hepatocytes

The following article provides evidence that cellular calcium controls the activity of glycogen synthase in all three major glycogen storage tissues; muscle, fat, and liver. Depletion of cellular calcium resulted in a moderate increase of glycogen synthase %I activities in intact mouse diaphragms, in isolated rat adipocytes, and in rat hepatocytes. The increase in %I activity of glycogen synthase was more pronounced when the uridine di-phosphoglucose concentration in the glycogen synthase assay was lowered from 4.4 mM to 0.2 mM. Calcium depletion resulted in an approximately two-fold decrease in the Ka values for glucose-6-phosphate in all three tissues. The activities of glycogen synthase also correlated well with the content of cell-associated calcium in rat hepatocytes. The glucose-6-phosphate independent activities of glycogen synthase in extracts of calcium-replete and calcium-depleted tissue approached the same value following the exposure to crude phosphoprotein phosphatase. The activities of glycogen phosphorylase decreased in calcium-depleted tissues and cells. Insulin stimulated the activity of glycogen synthase in muscle and fat in the absence of added sugar and in the absence of extracellular calcium. It is concluded that glycogen synthase is under the control of calcium in the three main glycogen storage tissues. The actions of calcium are probably mediated through the actions of calcium-sensitive protein kinase(s).