Binding of F-protein (phosphofructokinase) to F-actin

By the use of sedimentation method the interaction of F-protein (phosphofructokinase) with F-actin has been studied in 0.1 M KCl, 10 mM K-phosphate buffer, pH 6.5. The calculated value of the constant of F-protein binding to F-actin is (7.3 +/- 1.0) X 10(5) M-1. The number of the F-protein binding sites calculated per chain weight of 80,000 is 0.43. The binding of F-protein to F-actin was found to be affected by pH-value.     

Influence of C-protein on mechano-chemical properties and structure of reconstituted actomyosin

C-protein on the mechano-chemical properties (ATPase activity and superprecipitation) of actomyosin systems has been investigated. The presence of C-protein in AM-complexes has been shown to decrease the rate of superprecipitation (SPP) and simultaneously increase the ATPase activity. Both effects of C-protein are dependent on its quantity in the system. Tropomyosin decreased considerably but does not eliminate completely the inhibitory influence of C-protein on the SPP. Electron microscopy does not reveal considerable structural differences in the initial AM-complexes depending on the presence or absence of C-protein. It is supposed that the discovered effects of C-protein on the behaviour of AM-systems are determined by the fine local structural and (or) charge changes produced by C-protein in the region of myosin cross-bridges, which in its turn results in a modification of the actin-myosin interaction. Possible participation of C-protein in the regulation of the interaction of thin and thick filaments in the muscle is discussed.     

Autoimmune disorders in liqvidators 11 years after the Chernobyl accident

We studied long-lasting consequences of the low-doses irradiation on the immune system of 71 clean-up workers who participated in the emergency work after the Chernobyl Plant accident in 1986 and 25 healthy donors from Belarus. In sera of the workers the level of autoantibodies to thyroid gland antigens (thyroglobulin and microsomal fraction of thyroid gland) was increased in 48% of cases, the level of autoantibodies to lens oculis antigen was increased in 44% of cases; the level of circulating immune complexes was elevated in 55%, and the serum level of thyroglobulin in 60% of people. Immunological disorders were found without any definite clinical evidences of diseases and this allows us to consider the examined contingent as a group of risk for the development of autoimmune pathology in the future.     

Aerobic training increases the expression of adiponectin receptor genes in the peripheral blood mononuclear cells of young men

Little is known about the effect of exercise training on the expression of adiponectin receptor genes in peripheral blood mononuclear cells (PBMCs). In this study, we investigated the effects of aerobic training on the expression of AdipoR1 and AidpoR2 mRNAs in PBMCs, whole body insulin sensitivity, and circulating adiponectins in men. Thirty young men were randomly assigned to either a control (n=15) or an exercise (n=15) group. Subjects assigned to the exercise group underwent a 12-week jogging and/or running programme on a motor-driven treadmill at an intensity of 60%-75% of the age-based maximum heart rate with duration of 40 minutes per session and a frequency of 5 days per week. Two-way mixed ANOVA with repeated measures was used to test any significant time-by-group interaction effects for the measured variables at p=0.05. We found significant time-by-group interaction effects for waist circumference (p=0.001), VO_2max (p<0.001), fasting insulin (p=0.016), homeostasis model assessment for insulin resistance (HOMA-IR) (p=0.010), area under the curve (AUC) for insulin response during the 75-g oral glucose tolerance test (p=0.002), high-molecular weight (HMW) adiponectin (p=0.016), and the PBMC mRNA levels of AdipoR1 (p<0.001) and AdipoR2 (p=0.001). The exercise group had significantly increased mRNA levels of AdipoR1 and AdipoR2 in PBMCs, along with increased whole body insulin sensitivity and HMW adiponectin, decreased waist circumference, and increased VO_2max compared with the control group. In summary, the current findings suggest that exercise training modulates the expression of AdipoR1 and AdipoR2 mRNAs in PBMCs, implying that manipulation of the expression of these genes could be a potential surrogate for lifestyle intervention-mediated improvements of whole body insulin sensitivity and glucose homeostasis.     

Ammonia affects the activity and expression of soluble and particulate GC in cultured rat astrocytes

Neurotoxic effects of ammonia are mediated by increased accumulation of nitric oxide (NO), which combines with free radicals to form a highly toxic compound, peroxynitrite. Previous experiments in vivo and in vitro have suggested that this phenomenon engages neuron-derived NO and is coupled to changes in the accumulation of cGMP. The present study accounted for the facts that: (i) astrocytes, not neurons are the morphological target of ammonia, and (ii) both NO-dependent, soluble (sGC) and NO-independent, particulate guanylate cyclase (pGC) mediate cGMP production in the cells. Neocortical rat astrocytes were treated for 1 or 24 h with 5 mM ammonium chloride ("ammonia") and then subjected to: (i) cGMP measurement, and (ii) mRNA and/or protein expression analysis of alpha1 and beta1 subunits of sGC and two pGC forms: pGC-A and pGC-B. Treatment with ammonia for 1h increased accumulation of cGMP and sGCbeta1 mRNA expression, without producing significant changes in the protein expression. This was followed by a decrease of cGMP level at 24 h treatment, associated with a decreased expression of sGCbeta1 and sGCalpha1 mRNA and sGCbeta1 protein. Expression of pGC-A and pGC-B mRNA was elevated in ammonia-treated astrocytes after 24 h. Accordingly, increased cGMP accumulation was noted in the presence of a specific sGC inhibitor (ODQ). The results show that ammonia affects cGMP production in astrocytes, and that this may involve not only sGC but also pGC.     

Genetic and environmental heterogeneity of residual variance of weight traits in Nellore beef cattle

Background

Many studies have provided evidence of the existence of genetic heterogeneity of environmental variance, suggesting that it could be exploited to improve robustness and uniformity of livestock by selection. However, little is known about the perspectives of such a selection strategy in beef cattle.

Methods

A two-step approach was applied to study the genetic heterogeneity of residual variance of weight gain from birth to weaning and long-yearling weight in a Nellore beef cattle population. First, an animal model was fitted to the data and second, the influence of additive and environmental effects on the residual variance of these traits was investigated with different models, in which the log squared estimated residuals for each phenotypic record were analyzed using the restricted maximum likelihood method. Monte Carlo simulation was performed to assess the reliability of variance component estimates from the second step and the accuracy of estimated breeding values for residual variation.

Results

The results suggest that both genetic and environmental factors have an effect on the residual variance of weight gain from birth to weaning and long-yearling in Nellore beef cattle and that uniformity of these traits could be improved by selecting for lower residual variance, when considering a large amount of information to predict genetic merit for this criterion. Simulations suggested that using the two-step approach would lead to biased estimates of variance components, such that more adequate methods are needed to study the genetic heterogeneity of residual variance in beef cattle.     

Notch signaling in intestinal homeostasis across species: the cases of Drosophila, Zebrafish and the mouse

Notch signaling has been recently shown to have a fundamental role in stem cell maintenance and control of proper homeostasis in the intestine of different species. Here, we briefly review the current literature on Notch signals in the intestine of Drosophila, Zebrafish and the mouse, and try to highlight conserved and divergent Notch functions across species. Notch signals show a remarkably conserved role in skewing cell fate choices in intestinal lineages throughout evolution. Genetic analysis demonstrates that loss of Notch signaling invariably leads to increased numbers of secretory cells and loss of enterocytes, while gain of Notch function will completely block secretory cell differentiation. Finally, we discuss the potential contribution of Notch signaling to the initiation of colorectal cancer by controlling the maintenance of the undifferentiated state of intestinal neoplastic cells and speculate on the therapeutic consequences of affecting cancer stem cells.     

Consensus statement understanding health and malnutrition through a systems approach: the ENOUGH program for early life

Nutrition research, like most biomedical disciplines, adopted and often uses experimental approaches based on Beadle and Tatum’s one gene—one polypeptide hypothesis, thereby reducing biological processes to single reactions or pathways. Systems thinking is needed to understand the complexity of health and disease processes requiring measurements of physiological processes, as well as environmental and social factors, which may alter the expression of genetic information. Analysis of physiological processes with omics technologies to assess systems’ responses has only become available over the past decade and remains costly. Studies of environmental and social conditions known to alter health are often not connected to biomedical research. While these facts are widely accepted, developing and conducting comprehensive research programs for health are often beyond financial and human resources of single research groups. We propose a new research program on essential nutrients for optimal underpinning of growth and health (ENOUGH) that will use systems approaches with more comprehensive measurements and biostatistical analysis of the many biological and environmental factors that influence undernutrition. Creating a knowledge base for nutrition and health is a necessary first step toward developing solutions targeted to different populations in diverse social and physical environments for the two billion undernourished people in developed and developing economies.     

Similarity of adhesion to phagocytosis: macrophage interaction with different substrates

Similarity between adhesion and phagocytosis is shown in the case of macrophages. Both adhesion of macrophages to polystyrene and phagocytosis of polystyrene particles (latex) do not depend much on the temperature and are not inhibited with iodoacetate. In contrast, both cell adhesion to adsorbed immunoglobulin G and phagocytosis of erythrocytes opsonized with immunoglobulin G, which are mediated with Fc-receptors, have some characteristic temperature dependence and are inhibited with iodoacetate. It may be concluded that it is the type of substrate, rather than its size, that determines mechanisms of adhesion and phagocytosis.