Regulatory function of the nitrogen metabolism of insects. Urea decomposition and silkworm feeds.

In cells of all domains of life, reversible lysine acetylation modulates the function of proteins involved in central cellular processes such as metabolism. In this study, we demonstrate that the nitrogen regulator GlnR of the actinomycete Saccharopolyspora erythraea directly regulates transcription of the acuA gene (SACE_5148), which encodes a Gcn5-type lysine acetyltransferase. We found that AcuA acetylates two glutamine synthetases (GlnA1 and GlnA4) and that this lysine acetylation inactivated GlnA4 (GSII) but had no significant effect on GlnA1 (GSI-β) activity under the conditions tested. Instead, acetylation of GlnA1 led to a gain-of-function that modulated its interaction with the GlnR regulator and enhanced GlnR–DNA binding. It was observed that this regulatory function of acetylated GSI-β enzymes is highly conserved across actinomycetes. In turn, GlnR controls the catalytic and regulatory activities (intracellular acetylation levels) of glutamine synthetases at the transcriptional and posttranslational levels, indicating an autofeedback loop that regulates nitrogen metabolism in response to environmental change. Thus, this GlnR-mediated acetylation pathway provides a signaling cascade that acts from nutrient sensing to acetylation of proteins to feedback regulation. This work presents significant new insights at the molecular level into the mechanisms underlying the regulation of protein acetylation and nitrogen metabolism in actinomycetes.

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The yeast prion protein Ure2: insights into the mechanism of amyloid formation

Biochemical Society Transactions ◽

10.1042/bst0391359 ◽

2011 ◽

Vol 39 (5) ◽

pp. 1359-1364 ◽

Cited By ~ 1

Author(s):

Li-Jun Chen ◽

Elizabeth B. Sawyer ◽

Sarah Perrett

Keyword(s):

Saccharomyces Cerevisiae ◽

Conformational Change ◽

Nitrogen Metabolism ◽

Prion Protein ◽

Molecular Chaperones ◽

Fibril Formation ◽

Regulatory Function ◽

Amyloid Formation ◽

Yeast Prion

Ure2, a regulator of nitrogen metabolism, is the protein determinant of the [URE3] prion state in Saccharomyces cerevisiae. Upon conversion into the prion form, Ure2 undergoes a heritable conformational change to an amyloid-like aggregated state and loses its regulatory function. A number of molecular chaperones have been found to affect the prion properties of Ure2. The studies carried out in our laboratory have been aimed at elucidating the structure of Ure2 fibrils, the mechanism of amyloid formation and the effect of chaperones on the fibril formation of Ure2.

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Emotions Under the Skin

Journal of Psychophysiology ◽

10.1027/0269-8803/a000147 ◽

2015 ◽

Vol 29 (4) ◽

pp. 161-170 ◽

Cited By ~ 15

Author(s):

Catarina Silva ◽

Ana Cláudia Ferreira ◽

Isabel Soares ◽

Francisco Esteves

Keyword(s):

Attachment Style ◽

Attachment Styles ◽

The Other ◽

Regulatory Function ◽

Physiological Reactivity ◽

Emotional Stimuli ◽

Skin Conductance Responses ◽

Lower Accuracy ◽

Emotional Pictures ◽

Valence And Arousal

Abstract. The present study examined physiological reactivity to emotional stimuli as a function of attachment style. Skin conductance responses (SCRs) and heart rate (HR) changes were simultaneously recorded while participants engaged in a visual attentional task. The task included positive, neutral, and negative emotional pictures, and required the identification of a target (neutral picture rotated 90° to the left or right), among a stream of pictures in which an emotional distracter (positive or negative) was presented. Participants additionally rated each of the emotional distracters for valence and arousal. Behavioral results on the attentional task showed that positive pictures facilitated overall target detection for all participants, compared to negative and neutral pictures, and that anxiously attached participants had significantly lower accuracy scores, relative to the other groups. Affective ratings indicated that positive pictures were rated as being more pleasant than negative ones, although no differences were found in HR changes to picture valence. In contrast, negative pictures were evaluated as being highly arousing. Consistent with this, negative pictures elicited larger SCRs in both insecure anxious and avoidant groups, especially for the anxious while the secure group showed SCRs unaffected by stimuli’s arousal. Present results show that individuals with different attachment styles reveal distinct patterns of attentional bias, appraisal, and physiological reactivity toward emotionally arousing stimuli. These findings further highlight the regulatory function of the attachment system.

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DEVELOPMENT OF AN EXPERIMENTAL MODEL OF AVITAMINOSIS F

Grain Products and Mixed Fodder’s ◽

10.15673/gpmf.v20i2.1764 ◽

2020 ◽

Vol 20 (2) ◽

pp. 38-40

Author(s):

A. Levitsky ◽

A. Lapinska ◽

I. Selivanskaya

Keyword(s):

Fatty Acids ◽

Experimental Model ◽

Unsaturated Fatty Acids ◽

Saturated Fatty Acids ◽

Coconut Oil ◽

The Body ◽

Regulatory Function ◽

Omega 3 ◽

White Rats ◽

Arachidonic Acids

The article analyzes the role of essential polyunsaturated fatty acids (PUFA), especially omega-3 series in humans and animals. The biosynthesis of essential PUFA in humans and animals is very limited, so they must be consumed with food (feed). Тhe ratio of omega-3 and omega-6 PUFA is very important. Biomembranes of animal cells contain about 30% PUFA with a ratio of ω-6/ ω-3 1-2. As this ratio increases, the physicochemical properties of biomembranes and the functional activity of their receptors change. The regulatory function of essential PUFA is that in the body under the action of oxygenase enzymes (cyclooxygenase, lipoxygenase) are formed extremely active hormone-like substances (eicosanoids and docosanoids), which affect a number of physiological processes: inflammation, immunity, metabolism. Moreover, ω-6 PUFA form eicosanoids, which have pro-inflammatory, immunosuppressive properties, and ω-3 PUFAs form eicosanoids and docosanoids, which have anti-inflammatory and immunostimulatory properties. Deficiency of essential PUFA, and especially ω-3 PUFA, leads to impaired development of the body and its state of health, which are manifestations of avitaminosis F. Prevention and treatment of avitaminosis F is carried out with drugs that contain PUFA. To create new, more effective vitamin F preparations, it is necessary to reproduce the model of vitamin F deficiency. An experimental model of vitamin F deficiency in white rats kept on a fat –free diet with the addition of coconut oil, which is almost completely free of unsaturated fatty acids, and saturated fatty acids make up almost 99 % of all fatty acids was developed. The total content of ω-6 PUFA (sum of linoleic and arachidonic acids), the content of ω-3 PUFA (α-linolenic, eicosapentaenoic and docosahexaenoic acids) in neutral lipids (triglycerides and cholesterol esters) defined. Тhe content of ω-6 PUFA under the influence of coconut oil decreased by 3.3 times, and the content of ω-3 PUFA - by 7.5 times. Тhe influence of coconut oil, the content of ω-6 PUFA decreased by 2.1 times, and the content of ω-3 PUFA - by 2.8 times. The most strongly reduces the content of ω-3 PUFA, namely eicosapentaenoic, coconut oil, starting from 5 %. Consumption of FFD with a content of 15 % coconut oil reduces the content of eicosapentaenoic acid to zero, ie we have an absolute deficiency of one of the most important essential PUFAs, which determined the presence of vitamin F deficiency.

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