Yeast pyruvate kinase: a mutant form catalytically insensitive to fructose 1,6-bisphosphate

The paper describes some of the characteristic properties of an altered form of pyruvate kinase from a mutant of Saccharomyces cerevisiae. The partially purified enzyme does not require fructose 1,6-bisphosphate for activity but is stabilised in its presence both at low and at high temperatures. The enzyme displays in the absence of fructose 1,6-bisphosphate hyperbolic kinetics with phosphoenolpyruvate (Km, 0.11 mM), ADP (Km, 0.12 mM) and K+ (Km, 11 mM). Sedimentation velocity experiments indicate that the mutated enzyme and the wild type enzyme have s20, w values of 8.9 and 8.6 S respectively. The mutant with the pyruvate kinase insensitive to fructose 1,6-bisphosphate is capable of growing on synthetic media with alcohol or malate as the sole carbon source. The steady-state intracellular levels of phosphoenolpyruvate in the mutant suggest mechanisms that prevent depletion of this metabolite despite an active pyruvate kinase. Spontaneous reversion of this mutant yields clones with normal enzyme activated by fructose 1,6-bisphosphate

Phosphofructokinase mutants of yeast. Biochemistry and genetics

Mutants of Saccharomyces cerevisiae completely lacking the soluble glycolytic enzyme fructose-6-P kinase are described. The mutations are semidominant, do not complement one another, and define a gene PFK1 located 28-cm distal to rna1 on the extended right arm of chromosome XIII. Of 10 independent mutants, 3 can be suppressed by ochre suppressors. All mutants examined synthesize proteins that cross-react to the antibody against the purified yeast P-fructokinase. The enzyme in spontaneous revertants is distinguishable from the wild type enzyme with respect to thermolability and ATP inhibition. The locus PFK1 thus defines the structural gene of the enzyme. The pfk1 mutants are not leaky in vivo. All the glucose consumed by a double mutant lacking both P-fructokinase and 6-P-gluconate dehydrogenase ends up as 6-P-gluconate, yet the pfk1 mutants can glycolyze and grow on glucose in air. The cell mass produced per unit of glucose also remains unchanged. Anaerobically, however, growth does not take place, nor does glycolysis. P-fructokinase is thus a dispensable enzyme for aerobic growth, but indispensable for anaerobic growth. The properties of pfk1 mutants suggest that yeast has an alternative mechanism for the aerobic metabolism of fructose-6-P, presumably through the recently reported particulate P-fructokinas

Alcohol industry self-regulation: Who is it really protecting

Self-regulation has been promoted by the alcohol industry as a sufficient means of regulating alcohol marketing activities. However, evidence suggests that the guidelines of self-regulated alcohol marketing codes are violated routinely, resulting in excessive alcohol marketing exposure to youth and the use of content that is potentially harmful to youth and other vulnerable populations. If the alcohol industry does not adhere to its own regulations the purpose and design of these codes should be questioned. Indeed, implementation of alcohol marketing self-regulation in Brazil, the United Kingdom and the United States was likely to delay statutory regulation rather than to promote public health. Moreover, current self-regulation codes suffer from vague language that may allow the industry to circumvent the guidelines, loopholes that may obstruct the implementation of the codes, lax exposure guidelines that can allow excessive youth exposure, even if properly followed, and a standard of review that may be inappropriate for protecting vulnerable populations. Greater public health benefits may be realized if legislative restrictions were applied to alcohol marketing, and strict statutory alcohol marketing regulations have been implemented and defended successfully in the European Union, with European courts declaring that restrictions on alcohol marketing are proportional to the benefits to public health. In contrast, attempts to restrict alcohol marketing activities in the United States have occurred through private litigation and have been unsuccessful. None the less, repeated violations of industry codes may provide legislators with sufficient justification to pass new legislation and for such legislation to withstand constitutional review in the United States and elsewhere.Alcohol Research UKInstitute of Alcohol StudiesUniv Connecticut, Sch Med, Dept Community Med & Hlth Care, Farmington, CT USAUniversidade Federal de São Paulo (UNIFESP), Dept Psychiat, Sao Paulo, BrazilDepartment of Psychiatry, Universidade Federal de São Paulo (UNIFESP), São Paulo, BrazilWeb of Scienc

Nerve stretch injury induced pain pattern and changes in sensory ganglia in a clinically relevant model of limb-lengthening in rabbits.

We used a model of tibial lengthening in rabbits to study the postoperative pain pattern during limb-lengthening and morphological changes in the dorsal root ganglia (DRG), including alteration of substance P (SP) expression. Four groups of animals (naive; OG: osteotomised only group; SDG/FDG: slow/fast distraction groups, with 1 mm/3 mm lengthening a day, respectively) were used. Signs of increasing postoperative pain were detected until the 10(th) postoperative day in OG/SDG/FDG, then they decreased in OG but remained higher in SDG/FDG until the distraction finished, suggesting that the pain response is based mainly on surgical trauma until the 10(th) day, while the lengthening extended its duration and increased its intensity. The only morphological change observed in the DRGs was the presence of large vacuoles in some large neurons of OG/SDG/FDG. Cell size analysis of the S1 DRGs showed no cell loss in any of the three groups; a significant increase in the number of SP-positive large DRG cells in the OG; and a significant decrease in the number of SP-immunoreactive small DRG neurons in the SDG/FDG. Faster and larger distraction resulted in more severe signs of pain sensation, and further reduced the number of SP-positive small cells, compared to slow distraction

Mutations in the regulatory subunit of soluble phosphofructokinase from yeast

Mutant alleles of the gene PFK2 have been obtained that alter the sensitivity to ATP inhibition of the soluble yeast phosphofructokinase. One of the alleles makes the enzyme sensitive to micromolar concentrations of ATP. Intragenic revertants of PFK2 mutants confirm that the PFK2 gene determines not only the regulatory properties of the soluble enzyme but also the catalytic activity of particulate phosphofructokinase

Past Tense Formation in Williams Syndrome

It has been claimed that in the language systems of people with Williams syndrome (WS), syntax is intact but lexical memory is impaired. Evidence has come from past tense elicitation tasks with a small number of participants where individuals with WS are said to have a specific deficit in forming irregular past tenses. However, typically developing children also show poorer performance on irregulars than regulars in these tasks, and one of the central features of WS language development is that it is delayed. We compared the performance of 21 participants with WS on two past tense elicitation tasks with that of four typically developing control groups, at ages 6, 8, 10, and adult. When verbal mental age was controlled for, participants in the WS group displayed no selective deficit in irregular past tense performance. However, there was evidence for lower levels of generalisation to novel strings. This is consistent with the hypothesis that the WS language system is delayed because it has developed under different constraints, constraints that perhaps include atypical phonological representations. The results are discussed in relation to dual-mechanism and connectionist computational models of language development, and to the possible differential weight given to phonology versus semantics in WS development

Cognitive mapping style relates to posterior-anterior hippocampal volume ratio

As London taxi drivers acquire ‘the knowledge’ and develop a detailed cognitive map of London, their posterior hippocampi (pHPC) gradually increase in volume, reflecting an increasing pHPC/aHPC volume ratio. In the mnemonic domain, greater pHPC/aHPC volume ratios in young adults have been found to relate to better recollection ability, indicating that the balance between pHPC and aHPC volumes might be reflective of cross-domain individual differences. Here, we examined participants’ self-reported use of cognitive map-based navigational strategies in relation to their pHPC/aHPC hippocampal volume ratio. We find that greater reported cognitive map use was related to significantly greater posterior, relative to anterior, hippocampal volume in two separate samples of young adults. Further, greater reported cognitive map usage correlated with better performance on a self-initiated navigation task. Together, these data help to advance our understanding of differences between aHPC and pHPC and the greater role of pHPC in spatial mapping

KARAKTERISTIK MUTU MIKROENKAPSULAT MINYAK BUAH MERAH (Pandanus conoideus) DENGAN PERBANDINGAN KONSENTRAS: The Characteristics of Quality of Microencapsulate Red Fruit Oil (Pandanus conoideus) With a Comparison of the Composition of the Emulsifying Material and the Coating Material

ABSTRACT             Red fruit oil is very sensitive to oxygen. One effort that can be done to improve its stability is using microencapsulation technology. This study aims to produce a stable formula of red fruit oil microencapsulated with the best quality characteristics. Formulation of emulsion of red fruit oil to be encapsulated using 11% degumed red fruit oil, mixture of emulsifier and stabilizer (maltodextrin, gum arab, gelatin, tween 80 and Carboxymethyl Celluloce (CMC)) 22%, and water 67%. The emulsion materials are homogenized and dried using a spray dryer. The parameters observed include the color, viscosity and stability of the emulsion, as well as the physicochemical character and the active components of red fruit microcapsules inamely rendemen, color, moisture content, solubility, total carotenoids and carotenoid retention. The results of this study indicate that the concentration of the coating material and the stabilizer affect the quality of the resulting red fruit oil microencapsules. The formula of stable red fruit oil microenkapulates (F4 and F5) consisting of degummed red fruit oil (11%), maltodextrin (18%), gum arab (1.8-2.6%), gelatin (0.9-1.3%) ), CMC (0.4%) and tween 80 (0.4-0.9%). Comparison of oil fraction, fraction of dry matter and water fraction which can form microencapsulated red fruit oil comprises 11% degummed red fruit oil, 22% emulsifier, coating and stabilizer; and water 67%. Characteristics of red fruit oil microenkapsulat (F4 and F5) are old orange color, 29-30% rendement, 24-25% fat content, total carotenoid 108-111 ppm, carotenoid retention 47-48%, and 73-80% solubility. Keywords: microencapsulation, emulsion, red fruit (Pandanus conoideus) oil, carotenoid.   ABSTRAK Minyak buah merah bersifat sangat sensitif terhadap oksigen, salah satu upaya yang dapat dilakukan untuk meningkatkan stabilitasnya yaitu melalui teknologi mikroenkapsulasi. Penelitian ini bertujuan untuk mempelajari karakteristik mutu mikroenkapsulat minyak buah merah dengan perbandingan konsentrasi bahan pengemulsi (tween 80 dan CMC) dan bahan pelapis (maltodekstrin, gum arab dan gelatin). Formulasi emulsi minyak buah merah yang akan dienkapsulasi menggunakan minyak buah merah hasil degumming 11%, campuran bahan pengemulsi dan penstabil (maltodekstrin, gum arab, gelatin, tween 80 dan CMC) 22% dan air 67%. Bahan-bahan emulsi dihomogenisasi dan dikeringkan menggunakan spray dryer. Parameter yang diamati meliputi warna, kekentalan dan stabilitas emulsi, serta sifat fisikokimia (rendemen, warna, kelarutan, kadar air dan kadar lemak) dan komponen aktif (total karotenoid dan retensi karotenoid) mikrokapsul buah merah. Hasil penelitian ini menunjukkan bahwa konsentrasi bahan pengemulsi dan pelapis mempengaruhi kualitas mikroenkapsulat minyak buah merah yang dihasilkan. Formula F4 dan F5 adalah mikroenkapsulat minyak buah merah yang paling stabil dengan komposisi minyak buah merah hasil degumming (11%), maltodekstrin (18%), gum arab (1,8-2,6%), gelatin (0,9-1,3), CMC 0,4% dan tween 80 0,4-0,9%. Karakteristik mikroenkapsulat minyak buah merah (F4 dan F5) yaitu warna oranye tua, rendemen 29-30%, kadar lemak 24-25%, total karotenoid 108-111 ppm, retensi karotenoid 47-48%, dan kelarutan 73-80%. Kata Kunci: mikrokapsul, minyak buah merah (Pandanus conoideus), stabilitas minyak

Two-stage Stochastic Model using Benders' Decomposition for Large-scale Energy Resources Management in Smart grids

The ever-increasing penetration level of renewable energy and electric vehicles may threaten power grid operation. Dealing with uncertainty in smart grids is critical in order to mitigate possible issues. This research work proposes a two-stage stochastic model for large-scale energy resources scheduling for aggregators. The proposed model is designed for aggregators managing a smart grid. The idea is to address the challenge brought by the variability of demand, renewable energy, electric vehicles, and market price variations while pursuing cost minimization. Benders’ decomposition approach is implemented to improve the tractability of the original model and its’ computational burden. A realistic case study is presented using a real distribution network in Portugal with high penetration of renewable energy and electric vehicles. The results show the effectiveness and efficiency of the proposed approach when compared with a deterministic formulation and suggest that demand response and storage systems can mitigate the uncertainty.info:eu-repo/semantics/acceptedVersio