The effects of metformin therapy on BMI and biochemical markers among overweight children and adolescents [abstract]

Introduction: In the United States, overweight adolescents are likely to continue to gain weight over time and are more likely to become overweight adults. High rates of child and adolescent obesity leave physicians searching for ways to stop this trend. Methods: A retrospective study design was implemented to describe trends of obese adolescent patients who are prescribed metformin as part of treatment in the multidisciplinary adolescent obesity specialty clinic at the University of Missouri. Results: Of the 156 participants in this study, 55 (35%) were prescribed a variable dose of metformin, a drug commonly used for elevated insulin levels, at least once during their clinic visits. The majority of patients in this study (61%) had insulin levels that above 20, which defines hyperinsulinemia. In a chi-square analysis of the data, patients who were in higher BMI categories were more likely to have higher serum insulin levels (p=0.0285). In the analysis of the patients in the study over time, it was found that of the 131 patients who were seen for more than one visit, 111 (85%) of these patients had no increase in BMI. Discussion: The adolescent obesity clinic has shown to halt or reverse weight gain in most of the patients who came for more than one visit. While many factors, including counseling on lifestyle modification (diet and exercise), medication, and routine follow-up can be attributed to the patients' ability to stop weight gain, metformin appears to be a satisfactory adjuvant therapy in the clinical management of adolescent obesity, especially in patients with hyperinsulinemia

Coenzyme Q10 deficiencies: pathways in yeast and humans.

Coenzyme Q (ubiquinone or CoQ) is an essential lipid that plays a role in mitochondrial respiratory electron transport and serves as an important antioxidant. In human and yeast cells, CoQ synthesis derives from aromatic ring precursors and the isoprene biosynthetic pathway. Saccharomyces cerevisiae coq mutants provide a powerful model for our understanding of CoQ biosynthesis. This review focusses on the biosynthesis of CoQ in yeast and the relevance of this model to CoQ biosynthesis in human cells. The COQ1-COQ11 yeast genes are required for efficient biosynthesis of yeast CoQ. Expression of human homologs of yeast COQ1-COQ10 genes restore CoQ biosynthesis in the corresponding yeast coq mutants, indicating profound functional conservation. Thus, yeast provides a simple yet effective model to investigate and define the function and possible pathology of human COQ (yeast or human gene involved in CoQ biosynthesis) gene polymorphisms and mutations. Biosynthesis of CoQ in yeast and human cells depends on high molecular mass multisubunit complexes consisting of several of the COQ gene products, as well as CoQ itself and CoQ intermediates. The CoQ synthome in yeast or Complex Q in human cells, is essential for de novo biosynthesis of CoQ. Although some human CoQ deficiencies respond to dietary supplementation with CoQ, in general the uptake and assimilation of this very hydrophobic lipid is inefficient. Simple natural products may serve as alternate ring precursors in CoQ biosynthesis in both yeast and human cells, and these compounds may act to enhance biosynthesis of CoQ or may bypass certain deficient steps in the CoQ biosynthetic pathway

Factors affecting the activity of baker's compressed and active dry yeast : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Biotechnology at Massey University

Factors affecting the Activity of Baker's Compressed and Active Dry Yeast. Parameters important in the production of Baker's Yeast were correlated with the product's final activity. Activity was a measure of the gas evolved in a fermenting dough, expressed as mMCO2/hr/g yeast solids. The drying of Compressed Yeast to Active Dry Yeast was optimised in terms of the drying air. A tunnel tray drier was used to dry yeast to a 9% moisture content (dry weight). At 40°C. the optimum drying humidity was found to be 30-32% relative humidity. The leavening ability of yeast dried at 17% and 45% relative humidity decreased. A drying additive, 2% glyceryl monostearate, halved the drying time to 4 hours. Equations were developed to describe these observations as a function of relative humidity, drying time and additive concentration. The equilibrium relative humidity of stored dried yeast was found to be 32% at 20°C. Fermentation parameters were correlated with the activity of Compressed Yeast using an experimental design. Growth temperatures varied from 28°C. to 37°C., initial pH from 4 to 6, glucose concentrations from 0.5% to 3%, nitrogen concentrations from 0.3% to 1.2% and dissolved oxygen varied as either agitated or standing cultures. Factors significantly affecting cell yield and yeast activity were growth temperature, dissolved oxygen and glucose concentrations. Maximal yeast activity occurred at 0.5% glucose concentration, 28°C. and non-agitated conditions. A model was developed to describe yeast activity as a function of these variables. The observed optimal conditions for cell yield were similar to those for yeast activity except for the dissolved oxygen level. Maximum yeast activity of Compressed Yeast occurred in non-agitated fermentations, compared with cell yield which required agitated conditions to achieve the greatest cell yield. A rapid screening test for evaluating dried yeast was incorporated into the yeast activity analysis. This involved monitoring foam production during rehydration

Endoplasmic reticulum involvement in yeast cell death

Yeast cells undergo programed cell death (PCD) with characteristic markers associated with apoptosis in mammalian cells including chromatin breakage, nuclear fragmentation, reactive oxygen species generation, and metacaspase activation. Though significant research has focused on mitochondrial involvement in this phenomenon, more recent work with both Saccharomyces cerevisiae and Schizosaccharomyces pombe has also implicated the endoplasmic reticulum (ER) in yeast PCD. This minireview provides an overview of ER stress-associated cell death (ER-SAD) in yeast. It begins with a description of ER structure and function in yeast before moving to a discussion of ER-SAD in both mammalian and yeast cells. Three examples of yeast cell death associated with the ER will be highlighted here including inositol starvation, lipid toxicity, and the inhibition of N-glycosylation. It closes by suggesting ways to further examine the involvement of the ER in yeast cell death

External and internal triggers of cell death in yeast

In recent years, yeast was confirmed as a useful eukaryotic model system to decipher the complex mechanisms and networks occurring in higher eukaryotes, particularly in mammalian cells, in physiological as well in pathological conditions. This article focuses attention on the contribution of yeast in the study of a very complex scenario, because of the number and interconnection of pathways, represented by cell death. Yeast, although it is a unicellular organism, possesses the basal machinery of different kinds of cell death occurring in higher eukaryotes, i.e., apoptosis, regulated necrosis and autophagy. Here we report the current knowledge concerning the yeast orthologs of main mammalian cell death regulators and executors, the role of organelles and compartments, and the cellular phenotypes observed in the different forms of cell death in response to external and internal triggers. Thanks to the ease of genetic manipulation of this microorganism, yeast strains expressing human genes that promote or counteract cell death, onset of tumors and neurodegenerative diseases have been constructed. The effects on yeast cells of some of these genes are also presented

SSB-1 of the yeast Saccharomyces cerevisiae is a nucleolar-specific, silver-binding protein that is associated with the snR10 and snR11 small nuclear RNAs

SSB-1, the yeast single-strand RNA-binding protein, is demonstrated to be a yeast nucleolar-specific, silver-binding protein. In double-label immunofluorescence microscopy experiments antibodies to two other nucleolar proteins, RNA Pol I 190-kD and fibrillarin, were used to reveal the site of rRNA transcription; i.e., the fibrillar region of the nucleolus. SSB-1 colocalized with fibrillarin in a double-label immunofluorescence mapping experiment to the yeast nucleolus. SSB-1 is located, though, over a wider region of the nucleolus than the transcription site marker. Immunoprecipitations of yeast cell extracts with the SSB-1 antibody reveal that in 150 mM NaCl SSB-1 is bound to two small nuclear RNAs (snRNAs). These yeast snRNAs are snR10 and snR11, with snR10 being predominant. Since snR10 has been implicated in pre-rRNA processing, the association of SSB-1 and snR10 into a nucleolar snRNP particle indicates SSB-1 involvement in rRNA processing as well. Also, another yeast protein, SSB-36-kD, isolated by single- strand DNA chromatography, is shown to bind silver under the conditions used for nucleolar-specific staining. It is, most likely, another yeast nucleolar protein

"Poppy" yeast

I am old enough to have taken part in the international project to sequence the first eukaryotic genome—that of Saccharomyces cerevisiae—which was released in 1996. Twenty years later, scientists from academic and commercial institutions are now involved in the first wholesale construction of a eukaryotic genome: the Yeast 2.0 Project 1. The construction of whole genomes from scratch is defined as a bottom-up approach in synthetic biology. One of the aims of such work is to reduce genome size and construct a minimal cell factory for industrial applications. These synthetic yeast chromosomes will have unique features to allow scientists to easily reshuffle, eliminate or add new genes 2 in order to engineer cells for efficient production of a desired compound. Synthetic biologists also use a top-down approach to insert functional biological components into natural genomes. This has been used in yeast to produce natural molecules of pharmaceutical value, such as artemisinin acid 3. Currently, many compounds are not chemically synthesized because it is cheaper and more efficient to extract them from plants. The products of synthetic biology could easily replace plants as the source, especially as yeast fermentation is a matter of days, while plants need months or years to grow

Reductive Biotransformation of Ethyl Acetoacetate: A Comparative Studies using Free and Immobilized Whole Yeast Cells

Bioreduction of ethyl acetoacetate with free and immobilized yeast whole cell was achieved by using water and sucrose combination. After detachment from immobilized beads under basic condition, the corresponding ethyl(S)-(+)-3-hydroxybutanoate was isolated with 98 to 100% yield. Immobilized beads of yeast whole cell were prepared at different temperature which affects the morphology and physiology of the beads for the diffusion of the enzyme, which shown the maximum conversion of the substrate to products as compared to the free yeast whole cell

Development of "Blossom-Protect" - a yeast preparation for the reduction of blossom infections by fire blight

In organic apple-growing control agents are necessary to prevent the blossoms being infected by the fire blight pathogen Erwinia amylovora. Detached apple blossoms were used as an experimental model to develop preparations based on yeast isolates for use in the control of fire blight. Several yeast isolates reduced disease incidence in apple blossoms. The efficiency of yeast isolates was increased by developing a suitable formulation. This yeast preparation exhibited high efficiency in the control of fire blight in field-trials and will be marketed under the tradename "Blossom- Protect"

接合によりグルコアミラーゼ遺伝子STA1が発現したビール酵母の育種

Standard brewing yeast cannot utilize larger oligomers or dextrins, which represent about 25% of wort sugars. A brewing yeast strain that could ferment these additional sugars to ethanol would be useful for producing low-carbohydrate diabetic or low-calorie beers. In this study, a brewing yeast strain that secretes glucoamylase was constructed by mating. The resulting Saccharomyces cerevisiae 278/113371 yeast was MATa/ diploid, but expressed the glucoamylase gene STA1. At the early phase of the fermentation test in malt extract medium, the fermentation rate of the diploid STA1 strain was slower than those of both the parent strain S. cerevisiae MAFF113371 and the reference strain bottom-fermenting yeast Weihenstephan 34/70. At the later phase of the fermentation test, however, the fermentation rate of the STA1 yeast strain was faster than those of the other strains. The concentration of ethanol in the culture supernatant of the STA1 yeast strain after the fermentation test was higher than those of the others. The concentration of all maltooligosaccharides in the culture supernatant of the STA1 yeast strain after the fermentation test was lower than those of the parent and reference strains, whereas the concentrations of flavor compounds in the culture supernatant were higher. These effects are due to the glucoamylase secreted by the constructed STA1 yeast strain. In summary, a glucoamylase-secreting diploid yeast has been constructed by mating that will be useful for producing novel types of beer owing to its different fermentation pattern and concentrations of ethanol and flavor compound