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1.
[Conjugation to Branched Glycerol Oligomers, a Novel Strategy for Extremely Hydrophobic Agents].
Miyamoto, L, Abe, S, Nemoto, H, Tsuchiya, K
Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan. 2020;(8):1001-1006
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Abstract
Ascertaining the absorption, distribution, metabolism, and excretion (ADME) profile of drugs is one of the most crucial factors in the process of drug discovery. Since it is important to combine water solubility and cell permeability within the compound to achieve the desired ADME properties, an appropriate balance between lipophilicity and hydrophilicity is required. It is often necessary to facilitate hydrophilicity of very hydrophobic candidates, because quite lipophobic molecules are rarely hit as positive in molecular-targeted or cell-based screenings. For that purpose, it has been popular to conjugate hydrophobic molecules with polyethylene glycol (PEG). However, PEG is a polymer, and PEG-conjugated molecules are not uniform. Besides, the dosage should be much increased compared with the original molecule due to the increase in molecular weight. Therefore we have been developing alternative ways to endow hydrophobic compounds with extra hydrophilicity by conjugating with symmetrically branched glycerol oligomers. This technology is versatile and easily applicable to various hydrophobic compounds. Water-solubility of fenofibrate, one of the most hydrophobic medicines in clinical use, was facilitated by a factor of more than 2000, and its lipid-lowering effect in vivo improved more than ten-fold, by simply conjugating with branched glycerol trimer, for instance. Here we will briefly introduce the basic concepts and our successful experiences of applying branched glycerol oligomers including antitumor agents in terms of water-solubility, pharmacological effects, and pharmacokinetics, and merits and current issues will be discussed in this review.
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Valorification of crude glycerol for pure fractions of docosahexaenoic acid and β-carotene production by using Schizochytrium limacinum and Blakeslea trispora.
Bindea, M, Rusu, B, Rusu, A, Trif, M, Leopold, LF, Dulf, F, Vodnar, DC
Microbial cell factories. 2018;(1):97
Abstract
The goal of this research is the investigation of a way to maximize the production of docosahexaenoic acid (DHA) and β-carotene by optimizing the culture conditions of their sources, microalgae Schizochytrium limacinum and fungus Blakeslea trispora respectively, in a fermentation medium. The influencing factors in the fermentation process for producing DHA and β-carotene have proven to be: the concentration of carbon source (different glycerol crude and pure concentrations) for both of them, and in particular temperature for DHA and pH for β-carotene. Testing the effect of these parameters was determined: biomass, DHA and β-carotene concentration. The highest production by S. limacinum was obtained at 25 °C, while using a quantity of 90 g/L of glycerol (crude or pure) as a carbon source. Temperature was the main factor that influenced the biosynthesis of DHA. The quantification of DHA was made by GC-MS chromatography, followed by a purification process, with the end result of DHA in pure phase. The maximum quantities for β-carotene production were obtained with pH 7 and 60 g/L of crude glycerol. The results highlight the possibility of using crude glycerol as a low-cost substrates for growth of microalgae S. limacinum and of fungus B. trispora in order to obtain the crucial molecules: docosahexaenoic acid and β-carotene.
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Glycerol metabolism and transport in yeast and fungi: established knowledge and ambiguities.
Klein, M, Swinnen, S, Thevelein, JM, Nevoigt, E
Environmental microbiology. 2017;(3):878-893
Abstract
There is huge variability among yeasts with regard to their efficiency in utilizing glycerol as the sole source of carbon and energy. Certain species show growth rates with glycerol comparable to those reached with glucose as carbon source; others are virtually unable to utilize glycerol, especially in synthetic medium. Most of our current knowledge regarding glycerol uptake and catabolic pathways has been gained from studying laboratory strains of the model yeast Saccharomyces cerevisiae. The growth of these strains on glycerol is dependent on the presence of medium supplements such as amino acids and nucleobases. In contrast, there is only fragmentary knowledge about S. cerevisiae isolates able to grow in synthetic glycerol medium without such supplements as well as about growth of non-Saccharomyces yeast species on glycerol. Thus, more research is required to understand why certain strains and species show superior growth performance on glycerol compared with common S. cerevisiae laboratory strains. This mini-review summarizes what is known so far about the gene products and pathways involved in glycerol metabolism and transport in yeast and fungi as well as the regulation of these processes.
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Glycerol metabolism in hypersaline environments.
Oren, A
Environmental microbiology. 2017;(3):851-863
Abstract
Glycerol is a key compound for the understanding of the microbiology of hypersaline environments. At the highest salt concentrations the main or even sole primary producer is the green unicellular alga Dunaliella, which uses photosynthetically produced glycerol as osmotic stabilizer and compatible solute. Glycerol can be expected to be a major carbon source available to the heterotrophic communities of Archaea and Bacteria in hypersaline ecosystems. Use of Dunaliella has even been explored for the commercial production of glycerol. This article reviews our current understanding of glycerol metabolism in Dunaliella and of the ways glycerol can be degraded by heterotrophic prokaryote communities under aerobic and under anaerobic conditions. Dunaliella-derived glycerol may also be the key toward long-term survival of heterotrophic prokaryotes in fluid inclusions within salt crystals.
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Glycerol and testicular activity: the good, the bad and the ugly.
Crisóstomo, L, Alves, MG, Calamita, G, Sousa, M, Oliveira, PF
Molecular human reproduction. 2017;(11):725-737
Abstract
Over the past decades, there have been several studies suggesting that semen quality is declining. Interestingly, these observations are paired with a significant increase in the number of individuals diagnosed with metabolic diseases, including obesity and diabetes mellitus. Hence, it is tempting to hypothesize that obesity and its associated comorbidities and risk factors (such as a hypercaloric diets) impair the homeostasis of the male reproductive health, with a possible direct effect on the testes. The blood and interstitial fluids of obese individuals usually have increased levels of glycerol, notably due to triglyceride and phospholipid catabolism and high fructose intake. Glycerol is metabolized via intermediary metabolism by a group of reactions centred at the glycerol-3-phosphate shuttle, which links the metabolic pathway of glucose, lipids and oxidative phosphorylation, illustrating its high relevance for biological systems. Glycerol enters and exits the cells by the action of specialized carriers, known as aquaglyceroporins, whose functional importance for male reproductive health has emerged in the last few years. Notably, glycerol has antispermatogenic properties. When present in high concentration in the testis, it causes blood-testis barrier disruption, impairing tubular fluid homeostasis. Nevertheless, glycerol metabolism in testicular cells remains a matter of debate. Herein we discuss previous and current research concerning the role of glycerol and its metabolism in testicular cells, and how it can influence testicular activity.
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Yeast's balancing act between ethanol and glycerol production in low-alcohol wines.
Goold, HD, Kroukamp, H, Williams, TC, Paulsen, IT, Varela, C, Pretorius, IS
Microbial biotechnology. 2017;(2):264-278
Abstract
Alcohol is fundamental to the character of wine, yet too much can put a wine off-balance. A wine is regarded to be well balanced if its alcoholic strength, acidity, sweetness, fruitiness and tannin structure complement each other so that no single component dominates on the palate. Balancing a wine's positive fruit flavours with the optimal absolute and relative concentration of alcohol can be surprisingly difficult. Over the past three decades, consumers have increasingly demanded wine with richer and riper fruit flavour profiles. In response, grape and wine producers have extended harvest times to increase grape maturity and enhance the degree of fruit flavours and colour intensity. However, a higher degree of grape maturity results in increased grape sugar concentration, which in turn results in wines with elevated alcohol concentration. On average, the alcohol strength of red wines from many warm wine-producing regions globally rose by about 2% (v/v) during this period. Notwithstanding that many of these 'full-bodied, fruit-forward' wines are well balanced and sought after, there is also a significant consumer market segment that seeks lighter styles with less ethanol-derived 'hotness' on the palate. Consumer-focussed wine producers are developing and implementing several strategies in the vineyard and winery to reduce the alcohol concentration in wines produced from well-ripened grapes. In this context, Saccharomyces cerevisiae wine yeasts have proven to be a pivotal strategy to reduce ethanol formation during the fermentation of grape musts with high sugar content (> 240 g l-1 ). One of the approaches has been to develop 'low-alcohol' yeast strains which work by redirecting their carbon metabolism away from ethanol production to other metabolites, such as glycerol. This article reviews the current challenges of producing glycerol at the expense of ethanol. It also casts new light on yeast strain development programmes which, bolstered by synthetic genomics, could potentially overcome these challenges.
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Glycerin laxatives for prevention or treatment of feeding intolerance in very low birth weight infants.
Anabrees, J, Shah, VS, AlOsaimi, A, AlFaleh, K
The Cochrane database of systematic reviews. 2015;(9):CD010464
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Abstract
BACKGROUND Feeding intolerance is a common clinical problem among preterm infants. It may be an early sign of necrotising enterocolitis, sepsis or other serious gastrointestinal conditions, or it may result from gut immaturity with delayed passage of meconium. Glycerin laxatives stimulate passage of meconium by acting as an osmotic dehydrating agent and increasing osmotic pressure in the gut; they stimulate rectal contraction, potentially reducing the incidence of feeding intolerance. OBJECTIVES To assess the effectiveness and safety of glycerin laxatives (enemas/suppositories) for prevention or treatment of feeding intolerance in very low birth weight (VLBW) infants. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 4), MEDLINE, EMBASE and the Cumulative Index to Nursing and Allied Health Literature (CINAHL). We restricted our search to all randomised controlled trials and applied no language restrictions. We searched the references of identified studies and reviews on this topic and handsearched for additional articles. We searched the database maintained by the US National Institutes of Health (www.clinicaltrials.gov) and European trial registries to identify ongoing trials. SELECTION CRITERIA We considered only randomised or quasi-randomised controlled trials that enrolled preterm infants < 32 weeks' gestational age (GA) and/or < 1500 g birth weight. We included trials if they administered glycerin laxatives and measured at least one prespecified clinical outcome. DATA COLLECTION AND ANALYSIS We used standard methods of The Cochrane Collaboration and its Neonatal Group to assess methodological quality of trials, to collect data and to perform analyses. MAIN RESULTS We identified three trials that evaluated use of prophylactic glycerin laxatives in preterm infants. We identified no trials that evaluated therapeutic use of glycerin laxatives for feeding intolerance. Our review showed that prophylactic administration of glycerin laxatives did not reduce the time required to achieve full enteral feeds and did not influence secondary outcomes, including duration of hospital stay, mortality and weight at discharge. Prophylactic administration of glycerin laxatives resulted in failure of fewer infants to pass stool over the first 48 hours. Included trials reported no adverse events. AUTHORS' CONCLUSIONS Our review of available evidence for glycerin laxatives does not support the routine use of prophylactic glycerin laxatives in clinical practice. Additional studies are needed to confirm or refute the effectiveness and safety of glycerin laxatives for prevention or treatment of feeding intolerance in VLBW infants.
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The response to inositol: regulation of glycerolipid metabolism and stress response signaling in yeast.
Henry, SA, Gaspar, ML, Jesch, SA
Chemistry and physics of lipids. 2014;:23-43
Abstract
This article focuses on discoveries of the mechanisms governing the regulation of glycerolipid metabolism and stress response signaling in response to the phospholipid precursor, inositol. The regulation of glycerolipid lipid metabolism in yeast in response to inositol is highly complex, but increasingly well understood, and the roles of individual lipids in stress response are also increasingly well characterized. Discoveries that have emerged over several decades of genetic, molecular and biochemical analyses of metabolic, regulatory and signaling responses of yeast cells, both mutant and wild type, to the availability of the phospholipid precursor, inositol are discussed.
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Recent advances in biological production of 3-hydroxypropionic acid.
Kumar, V, Ashok, S, Park, S
Biotechnology advances. 2013;(6):945-61
Abstract
3-Hydroxypropionic acid (3-HP) is a valuable platform chemical that can be produced biologically from glucose or glycerol. This review article provides an overview and the current status of microbial 3-HP production. The constraints of microbial 3-HP production and possible solutions are also described. Finally, future prospects of biological 3-HP production are discussed.
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Impact of a heterogeneous liquid droplet on a dry surface: application to the pharmaceutical industry.
Bolleddula, DA, Berchielli, A, Aliseda, A
Advances in colloid and interface science. 2010;(2):144-59
Abstract
Droplet impact has been studied for over a hundred years dating back to the pioneering work of Worthington. In fact, much of his ingenuity contributed to modern day high speed photography. Over the past 40 years significant contributions in theoretical, numerical, and experimental work have been made. Droplet impact is a problem of fundamental importance due to the wealth of applications involved, namely, spray coating, spray painting, delivery of agricultural chemicals, spray cooling, inkjet printing, soil erosion due to rain drop impact, and turbine wear. Here we highlight one specific application, spray coating. Although most studies have focused their efforts on low viscosity Newtonian fluids, many industrial applications such as spray coating utilize more viscous and complex rheology liquids. Determining dominant effects and quantifying their behavior for colloidal suspensions and polymer solutions remains a challenge and thus has eluded much effort. In the last decade, it has been shown that introducing polymers to Newtonian solutions inhibits the rebounding of a drop upon impact, Bergeron et al. Furthermore Bartolo et al. concluded that the normal stress component of the elongational viscosity was responsible for the rebounding inhibition of polymer based non-Newtonian solutions. We aim to uncover the drop impact dynamics of highly viscous Newtonian and complex rheology liquids used in pharmaceutical coating processes. The generation and impact of drops of mm and microm size drops of coating liquids and glycerol/water mixtures on tablet surfaces are systematically studied over a range of We approximately O(1-300), Oh approximately O(10(-2)-1), and Re approximately O(1-700). We extend the range of Oh to values above 1, which are not available to previous studies of droplet impacts. Outcomes reveal that splashing and rebounding are completely inhibited and the role of wettability is negligible in the early stages of impact. The maximum spreading diameter of the drop is compared with three models demonstrating reasonable agreement.