Proteomic analysis of striated muscle

The techniques collectively known as proteomics are useful for characterizing the protein phenotype of a particular tissue or cell as well as quantitatively identifying differences in the levels of individual proteins following modulation of a tissue or cell. In the area of striated muscle research, proteomics has been a useful tool for identifying qualitative and quantitative changes in the striated muscle protein phenotype resulting from either disease or physiological modulation. Proteomics is useful for these investigations because many of the changes in the striated muscle phenotype resulting from either disease or changes in physiological state are qualitative and not quantitative changes. For example, modification of striated muscle proteins by phosphorylation and proteolytic cleavage are readily observed using proteomic technologies while these changes would not be identified using genomic technology. In this review, I will discuss the application of proteomic technology to striated muscle research, research designed to identify key protein changes that are either causal for or markers of a striated muscle disease or physiological condition.     

Role of corticofugal feedback in hearing

The auditory system consists of the ascending and descending (corticofugal) systems. The corticofugal system forms multiple feedback loops. Repetitive acoustic or auditory cortical electric stimulation activates the cortical neural net and the corticofugal system and evokes cortical plastic changes as well as subcortical plastic changes. These changes are short-term and are specific to the properties of the acoustic stimulus or electrically stimulated cortical neurons. These plastic changes are modulated by the neuromodulatory system. When the acoustic stimulus becomes behaviorally relevant to the animal through auditory fear conditioning or when the cortical electric stimulation is paired with an electric stimulation of the cholinergic basal forebrain, the cortical plastic changes become larger and long-term, whereas the subcortical changes stay short-term, although they also become larger. Acetylcholine plays an essential role in augmenting the plastic changes and in producing long-term cortical changes. The corticofugal system has multiple functions. One of the most important functions is the improvement and adjustment (reorganization) of subcortical auditory signal processing for cortical signal processing.     

Modeling implications of food resource aggregation on animal migration phenology

The distribution of poikilotherms is determined by the thermal structure of the marine environment that they are exposed to. Recent research has indicated that changes in migration phenology of beluga whales in the Arctic are triggered by changes in the thermal structure of the marine environment in their summering area. If sea temperatures reflect the spatial distribution of food resources, then changes in the thermal regime will affect how homogeneous or clumped food is distributed. We explore, by individual‐based modelling, the hypothesis that changes in migration phenology are not necessarily or exclusively triggered by changes in food abundance, but also by changes in the spatial aggregation of food. We found that the level of food aggregation can significantly affect the relationship between the timing of the start of migration to the winter grounds and the total prey capture of individuals. Our approach strongly indicates that changes in the spatial distribution of food resources should be considered for understanding and quantitatively predicting changes in the phenology of animal migration.     

Heritable Epigenetic Changes Alter Transgenerational Waveforms Maintained by Cycling Stores of Information

Our view of heredity can potentially be distorted by the ease of introducing heritable changes in the replicating gene sequences but not in the cycling assembly of regulators around gene sequences. Here, key experiments that have informed the understanding of heredity are reinterpreted to highlight this distortion and the possible variety of heritable changes are considered. Unlike heritable genetic changes, which are always associated with mutations in gene sequence, heritable epigenetic changes can be associated with physical or chemical changes in molecules or only changes in the system. The transmission of cycling stores along the continuous lineage of cells that connects successive generations creates waves of activity and localization of the molecules that together form the cell code for development in each generation. As a result, heritable epigenetic changes can include any that can alter a wave such as changes in form, midline, frequency, amplitude, or phase. Testing this integrated view of all heritable information will require the concerted application of multiple experimental approaches across generations.     

Regulation of Membrane Flexibility in Human Erythrocytes.

We have used spin-labels to detect prostaglandin E induced changes in erythrocyte membranes. The observed changes in spin-label resonance spectra can be mimicked in erythrocyte ghosts by loading them with cAMP or cGMP. These changes can also be observed by adding either of these cyclic nucleotides to intact cells. This entry of cyclic nucleotides into intact cells is blocked by an inhibitor of the anion channel. We suggest that the observed changes in paramagnetic resonance spectra are due to changes in lipid "fluidity" that are brought about by changes in the biochemical state of membrane-associated proteins (such as spectrin) and in the direct or indirect biophysical interactions of these proteins with membrane lipids.     

Moving beyond presence and absence when examining changes in species distributions

Species distributions are often simplified to binary representations of the ranges where they are present and absent. It is then common to look for changes in these ranges as indicators of the effects of climate change, the expansion or control of invasive species or the impact of human land‐use changes. We argue that there are inherent problems with this approach, and more emphasis should be placed on species relative abundance rather than just presence. The sampling effort required to be confident of absence is often impractical to achieve, and estimates of species range changes based on survey data are therefore inherently sensitive to sampling intensity. Species niches estimated using presence‐absence or presence‐only models are broader than those for abundance and may exaggerate the viability of small marginal sink populations. We demonstrate that it is possible to transform models of predicted probability of presence to expected abundance if the sampling intensity is known. Using case studies of Antarctic mosses and temperate rain forest trees, we demonstrate additional insights into biotic change that can be gained using this method. While species becoming locally extinct or colonising new areas are extreme and obviously important impacts of global environmental change, changes in abundance could still signal important changes in biological systems and be an early warning indicator of larger future changes.     

Actomyosin adenosine triphosphatase regulation by intramolecular myosin mechanisms. Myosin light chains functions and rod modification effects

Mechanisms of the actomyosin ATPase modulation via the myosin light chains (LC) in various myosin types are discussed. The essential LC increase the stability of the myosin heavy chains (HC) in the myosin heads and, under certain conditions, they can affect the degree of interaction of HC with actin. The regulatory LC (RLC) are sensitive to calcium binding on specific sites or to calcium activated phosphorylation. These factors induce changes of the RLC state followed by changes of the HC state in response to calcium concentration changes during the contractile process. Direct calcium binding or phosphorylation effects in various muscles are mediated by special types of RLC and HC. Several examples of actomyosin ATPase changes induced by modifications of the myosin rod are compared. A common feature of these effects is a possible involvement of certain configurational changes of the myosin molecule. These changes can affect the spatial position of the myosin heads and the myosin-actin interaction.     

The PP1 phosphatase flapwing regulates the activity of Merlin and Moesin in Drosophila

The signalling activities of Merlin and Moesin, two closely related members of the protein 4.1 Ezrin/Radixin/Moesin family, are regulated by conformational changes. These changes are regulated in turn by phosphorylation. The same sterile 20 kinase-Slik co-regulates Merlin or Moesin activity whereby phosphorylation inactivates Merlin, but activates Moesin. Thus, the corresponding coordinate activation of Merlin and inactivation of Moesin would require coordinated phosphatase activity. We find that Drosophila melanogaster protein phosphatase type 1 β (flapwing) fulfils this role, co-regulating dephosphorylation and altered activity of both Merlin and Moesin. Merlin or Moesin are detected in a complex with Flapwing both in-vitro and in-vivo. Directed changes in flapwing expression result in altered phosphorylation of both Merlin and Moesin. These changes in the levels of Merlin and Moesin phosphorylation following reduction of flapwing expression are associated with concomitant defects in epithelial integrity and increase in apoptosis in developing tissues such as wing imaginal discs. Functionally, the defects can be partially recapitulated by over expression of proteins that mimic constitutively phosphorylated or unphosphorylated Merlin or Moesin. Our results suggest that changes in the phosphorylation levels of Merlin and Moesin lead to changes in epithelial organization.     

Vascular smooth muscle in hypertension

The cause of the elevated arterial pressure in most forms of hypertension is an increase in total peripheral resistance. This brief review is directed toward an assessment of recent investigations contributing information about the factors responsible for this increased vascular resistance. Structural abnormalities in the vasculature that characterize the hypertensive process are 1) changes in the vascular media, 2) rarefication of the resistance vessels, and 3) lesions of the intimal vascular surface. These abnormalities are mainly the result of an adaptive process and are secondary to the increase in wall stress and/or to pathological damage to cellular components in the vessel wall. Functional alterations in the vascular smooth muscle are described as changes in agonist-smooth muscle interaction or plasma membrane permeability. These types of changes appear to play a primary, initiating role in the elevation of vascular resistance of hypertension. These alterations are not the result of an increase in wall stress and they often precede the development of high blood pressure. The functional changes are initiated by abnormal function of neurogenic, humoral, and/or myogenic changes that alter vascular smooth muscle activity.     

Floral color change: a widespread functional convergence

Ontogenetic color changes in fully turgid flowers are widespread throughout the angiosperms, and in many cases are known to provide signals for pollinators. A broad survey of flowering plants demonstrates that such color changes appear in at least 77 diverse families. Color-changing taxa occur commonly within what are considered derived lineages, and only rarely in early or primitive groups. The pattern of distribution of floral color change across orders, families, genera, and species demonstrates that the occurrence of the phenomenon within a group is not simply a result of phylogenetic history. Color changes can affect the whole flower or they can be localized, affecting at least nine floral parts or regions. The scale of color change (localized or whole-flower) is broadly correlated with the type of pollinator that characteristically visits the plant. Color changes can come about through seven distinct physiological mechanisms, involving anthocyanins, carotenoids, and betalains. Color changes due to appearance of anthocyanin are the most common, occurring in 68 families. Floral color change has clearly evolved independently many times, most likely in response to selection by visually oriented pollinators, and reflects a widespread functional convergence within the angiosperms.     

Clinical aspects of human circadian rhythms

Circadian rhythmicity can be important in the pathophysiology, diagnosis, and treatment of clinical disease. Due to the difficulties in conducting the necessary experimental work, it remains unknown whether approximately 24-h changes in pathophysiology or symptoms of many diseases are causally linked to endogenous circadian rhythms or to other diurnal factors that change across the day, such as changes in posture, activity, sleep or wake state, or metabolic changes associated with feeding or fasting. Until the physiology is accurately known, appropriate treatment cannot be designed. This review includes an overview of clinical disorders that are caused or affected by circadian or diurnal rhythms. The clinical side effects of disruption of circadian rhythmicity, such as in shiftwork, including the public health implications of the disrupted alertness and performance, are also discussed.     

Neuropeptide changes and neuroactive amino acids in CSF from humans and sheep with neuronal ceroid lipofuscinoses (NCLs,Batten disease)

Anomalies in neuropeptides and neuroactive amino acids have been postulated to play a role in neurodegeneration in a variety of diseases including the inherited neuronal ceroid lipofuscinoses (NCLs, Batten disease). These are often indicated by concentration changes in cerebrospinal fluid (CSF). Here we compare CSF neuropeptide concentrations in patients with the classical juvenile CLN3 form of NCL and the classical late infantile CLN2 form with neuropeptide and neuroactive amino acid concentrations in CSF from sheep with the late infantile variant CLN6 form.A marked disease related increase in CSF concentrations of neuron specific enolase and tau protein was noted in the juvenile CLN3 patients but this was not observed in an advanced CLN2 patient nor CLN6 affected sheep. No changes were noted in S-100b, GFAP or MBP in patients or of S-100b, GFAP or IGF-1 in affected sheep. There were no disease related changes in CSF concentrations of the neuroactive amino acids, aspartate, glutamate, serine, glutamine, glycine, taurine and GABA in these sheep.The changes observed in the CLN3 patients may be progressive markers of neurodegeneration, or of underlying metabolic changes perhaps associated with CLN3 specific changes in neuroactive amino acids, as have been postulated. The lack of changes in the CLN2 and CLN6 subjects indicate that these changes are not shared by the CLN2 or CLN6 forms and changes in CSF concentrations of these compounds are unreliable as biomarkers of neurodegeneration in the NCLs in general.     

Aging as a metagenetic process

Genomes of eukaryotic cells are so complicated that spontaneous processes lead inevitably to a continuous formation of egoistic genetic elements from the normal ones. These elements convert the intracellular Cosmos into Chaos and therefore they can be named chaonogenes. They behave as endogenous genetic parasites and are able to evaluate. The rate of their evolution is very rapid, which unevitably results in senescence and death of not only cells and multicellular organisms but also of populations and species, because chaonogens are transmitted from somatic cells to gametes. Populations of chaonogenes are very sensitive to environmental changes, and different sets of intracellular or extracellular changes are commonly used in nature to put obstracles in deleterious evolution of chaonogenes or to stop their evolution. These changes can be moderate (as at mitosis) or crude (as at meiosis), or they can be predicted (as programmed biochemical changes in the course of mitosis, meiosis and gametogenesis) or unpredicred (mutations, somatic crossingover, random association of gamets), but in all the cases they lead eventually to some degree of rejuvenation. In somatic cell populations, the process of senescence in slowed down by means of epigenetically determined changes and mitotic divisions, at which both kinds of changes (programmed and accidental) are moderate, and for this reason only a small part of dividing cells dies. At meiosis both kinds of changes are so acute that the majority of cells die, but the formation of gametes and zygotes becomes almost completely rejuvenated. Only mutations leading to very acute changes in intracellular conditions (whose products act on chaonogenes similarly as new antibiotics on bacteria) can save aging populations of multicellular organisms from death (as do L. N. Gumilev's "mutations of passionarity"), and only accidentally appearing "catastrophic" macromutations can give rise to new (and, of the same time, young) species. It is concluded that the induction of acute temporal biochemical changes in the inner environment is to slow down processes of human senescence and to lead to rejuvenation.     

Neuropeptide changes and neuroactive amino acids in CSF from humans and sheep with neuronal ceroid lipofuscinoses (NCLs, Batten disease)

Anomalies in neuropeptides and neuroactive amino acids have been postulated to play a role in neurodegeneration in a variety of diseases including the inherited neuronal ceroid lipofuscinoses (NCLs, Batten disease). These are often indicated by concentration changes in cerebrospinal fluid (CSF). Here we compare CSF neuropeptide concentrations in patients with the classical juvenile CLN3 form of NCL and the classical late infantile CLN2 form with neuropeptide and neuroactive amino acid concentrations in CSF from sheep with the late infantile variant CLN6 form.A marked disease related increase in CSF concentrations of neuron specific enolase and tau protein was noted in the juvenile CLN3 patients but this was not observed in an advanced CLN2 patient nor CLN6 affected sheep. No changes were noted in S-100b, GFAP or MBP in patients or of S-100b, GFAP or IGF-1 in affected sheep. There were no disease related changes in CSF concentrations of the neuroactive amino acids, aspartate, glutamate, serine, glutamine, glycine, taurine and GABA in these sheep.The changes observed in the CLN3 patients may be progressive markers of neurodegeneration, or of underlying metabolic changes perhaps associated with CLN3 specific changes in neuroactive amino acids, as have been postulated. The lack of changes in the CLN2 and CLN6 subjects indicate that these changes are not shared by the CLN2 or CLN6 forms and changes in CSF concentrations of these compounds are unreliable as biomarkers of neurodegeneration in the NCLs in general.     

Quantifying elasticity analysis: how external effectors cause changes to metabolic systems

The sites of action of external effectors, such as inhibitors or hormones, on metabolic systems can be described qualitatively by elasticity analysis, or quantitatively by regulation analysis. The use of the latter approach has been limited, due to its practical complexity. In this study, we report mathematical relationships that relate the finite changes in system variables (fluxes and metabolite concentrations) to changes in activity of metabolic processes brought about by a single step addition of an effector. The activation or inhibition of a process by an effector is measured from changes in flux and intermediate levels. The changes in activity of each process can be used to describe, semi-quantitatively, which activations or inhibitions of the system processes are important in bringing about the observed levels of system variables.     

Modifications of mammalian cell surfaces induced by sugars: Scanning electron microscopy

Substitution of galactose, xylose, or mannose for glucose in the growth medium of L cells or the addition of equal concentrations of the alternate sugars to glucose-containing medium results in marked morphologic changes. The changes are revealed by conventional staining for light microscopy and by scanning electron microscopy.L cells grow indefinitely on combinations of equal concentrations of glucose and galactose, xylose, or mannose. There appear to be no significant differences in growth rate on glucose compared to the combinations of sugars cited. Cells subcultured from glucose to the combinations while undergoing rapid multiplication show marked morphologic changes by light and scanning electron microscopy within 36 hr.Of particular note are the loss of microvilli; flattening of the cells; assumption of polygonal shape; prominence of nuclei and nucleoli; and changes in the structure and distribution of filopodia. Virtually all cells in the population exhibit the changes noted.     

Structural intermediates in folding of yeast iso-2 cytochrome c

The kinetic properties of the folding reactions of iso-2 cytochrome c from Saccharomyces cerevisiae have been investigated by stopped-flow and temperature-jump methods. Three different structural probes are compared: (1) absorbance changes in the visible reflecting changes in heme environment, (2) ultraviolet absorbance changes due to the exposure of aromatic groups to solvent, and (3) tryptophan fluorescence attributable principally to the average distance between the tryptophan residue (donor) and the heme (quencher). In addition, two probes either indicative of or correlated with function, ascorbic acid reducibility and the 695-nm absorbance band, have been used to monitor specifically the rate of formation of the native protein on refolding. The fastest phase observed (tau 3) has a measurable relative amplitude only when monitored by visible absorbance changes, suggesting that this reaction involves changes in heme environment in the absence of significant changes in the heme to tryptophan distance or in the extent to which aromatic groups are exposed to solvent. Different slow phases are observed when complete refolding is monitored by visible or ultraviolet absorbance (tau 1a) as opposed to tryptophan fluorescence (tau 1b), the fluorescence changes being complete on a time scale 4-8-fold faster than for absorbance. A mid-range kinetic phase (tau 2) is detected by all three structural probes. When ascorbic acid reducibility or 695-nm absorbance changes are used to monitor the rate of formation of the native protein, two phases are detected: tau 2 and tau 1a. Taken together these results demonstrate that kinetic phase tau 1b results in the formation of a structural intermediate in folding with fluorescence close to that of the native protein but with distinct absorbance properties.     

Testosterone-dependent changes in vivo and in vitro in the structure of the renal glomeruli of the teleost Gasterosteus aculeatus L.

Summary During the reproductive period of the male stickleback, structural and functional changes of the kidney take place, both in the glomeruli and in the renal tubule cells. The structural changes in the glomeruli involve almost all glomerular components and point to a reduction of the glomerular filtration rate. The purpose of this study was to investigate whether these changes are controlled by testosterone, indirectly or directly. In vivo experiments demonstrated that exposure of immature castrates for 8 days to methyltestosterone leads to activation of mesangial cells and podocytes, to slight expansion of mesangial matrix and slight thickening of basal lamina. Observations on cultured renal tissue showed that two androgens, 11-ketotestosterone and methyl testosterone, are also able to stimulate the secretory activity of podocytes and mesangial cells in vitro. The results therefore indicate, that most glomerular changes in male sticklebacks during the reproductive season are directly effected by testosterone.