Evolution and variation of the yeast (Saccharomyces) genome.
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In this review we describe the role of the yeast Saccharomyces in the development of human societies including the use of this organism in the making of wine, bread, beer, and distilled beverages. We also discuss the tremendous diversity of yeast found in natural (i.e., noninoculated) wine fermentations and the scientific uses of yeast over the past 60 years. In conclusion, we present ideas on the model of "genome renewal" and the use of this model to explain the mode by which yeast has evolved and how diversity can be generated. (+info)
Alcohol consumption in the Baltic Republics.
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STUDY OBJECTIVES: Premature mortality associated with alcohol intake is of particular concern in several countries of the former Soviet Union. This study explored self reported alcohol consumption (beer, wine, spirits) and its determinants in the Baltic Republics. DESIGN: Cross sectional surveys conducted in 1997. SETTINGS: Estonia, Latvia and Lithuania. PARTICIPANTS: Representative samples of adults age 19-64 (Estonia n=2010; Latvia n=2258; Lithuania n=2139). METHODS: Between country differences in the frequency of alcohol intake were estimated. The odds of consuming alcohol weekly according to socioeconomic characteristics (age, ethnicity, rural/urban area, education, income) were calculated using multiple logistic regression analyses, adjusting for all variables simultaneously. MAIN RESULTS: The proportion of respondents consuming alcohol weekly varied by country (p<0.001) (men: Estonia=61% Latvia=41% Lithuania=55%; women: Estonia=26% Latvia=8% Lithuania=14%). Within each country, this proportion decreased with age in both sexes (p<0. 001), and increased with income in women (p<0.01). In Estonia, the odds of drinking alcohol weekly was significantly lower in respondents of Russian than of Estonian ethnicity (odds ratios (OR) and 95% confidence intervals (95%CI): men=0.51 (0.36, 0.71); women=0. 57 (0.39, 0.81)). In Lithuania, the odds was higher in highly educated men than in those with a low education level (OR=1.48 (1.01, 2.17)). Daily alcohol intake was higher in Estonia than in the other countries, as was the percentage of respondents drinking heavily (equivalent to 80 g/day). CONCLUSIONS: Approximately half the men and one in six women in the Baltic States reported consuming alcohol at least weekly. Age and income were the strongest and most consistent correlates of the likelihood of consuming alcohol weekly. Ethnic differences were observed only in Estonia. (+info)
Application of a bioluminescence method for the beer industry: sensitivity of MicroStar-RMDS for detecting beer-spoilage bacteria. Rapid Microbe Detection System.
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We set up the original operating conditions of the MicroStar-Rapid Microbe Detection System (RMDS) to suppress false positives, which have kept this system from practical. The detection limit of our system was between 6.3 x 10(-16) mol and 3.1 x 10(-16) mol in terms of the amount of ATP, which is approximately equal to the ATP content of one yeast cell or 50 lactic acid bacteria cells. The detection time and the detection count were compared between the RMD method and the conventional plate count method (C.P.C. method) using 23 test samples of beer-spoilage Lactobacillus brevis. Judging from the detection time and detection count, 16-24 hours of cultivation for the RMD method corresponded to 40-96 hours of cultivation for the C.P.C. method. The RMD method reached a useful level for our practical use at the point of sensitivity. (+info)
Effects of high pressure on survival and metabolic activity of Lactobacillus plantarum TMW1.460.
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The application of high pressure (HP) for food preservation requires insight into mechanisms of HP-mediated cell injury and death. The HP inactivation in model beer of Lactobacillus plantarum TMW1.460, a beer-spoiling organism, was investigated at pressures ranging from 200 to 600 MPa. Surviving cells were characterized by determination of (i) cell viability and sublethal injury, (ii) membrane permeability to the fluorescent dyes propidium iodide (PI) and ethidium bromide (EB), (iii) metabolic activity with tetrazolium salts, and (iv) the activity of HorA, an ATP binding cassette-type multidrug resistance transporter conferring resistance to hop compounds. HP inactivation curves exhibited a shoulder, an exponential inactivation phase, and pronounced tailing caused by a barotolerant fraction of the population, about 1 in 10(6) cells. During exponential inactivation, more than 99.99% of cells were sublethally injured; however, no sublethal injury was detected in the barotolerant fraction of the culture. Sublethally injured cells were metabolically active, and loss of metabolic activity corresponded to the decrease of cell viability. Membrane damage measured by PI uptake occurred later than cell death, indicating that dye exclusion may be used as a fail-safe method for preliminary characterization of HP inactivation. An increase of membrane permeability to EB and a reduction of HorA activity were observed prior to the loss of cell viability, indicating loss of hop resistance of pressurized cells. Even mild HP treatments thus abolished the ability of cells to survive under adverse conditions. (+info)
Stability of aflatoxin B-1 and ochratoxin A in brewing.
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The stability of aflatoxin B-1 and ochratoxin A in brewing was investigated by adding the purified toxins to the raw materials at 1 and 10 mug/g levels during mashing in a conventional micro-brewing process. The results indicate that both toxins are stable to heat and are insensitive to cooker mash treatment. Both mycotoxins were partially removed in the mashing and brewing processes. About 14 to 18% and 27 to 28% of the added toxins were found in the final beers brewed from starting materials containing 1 and 10 mug, respectively, of either toxin per g. The possible route of transmission of mycotoxins into beer is discussed. (+info)
Riboprinting and 16S rRNA gene sequencing for identification of brewery Pediococcus isolates.
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A total of 46 brewery and 15 ATCC Pediococcus isolates were ribotyped using a Qualicon RiboPrinter. Of these, 41 isolates were identified as Pediococcus damnosus using EcoRI digestion. Three ATCC reference strains had patterns similar to each other and matched 17 of the brewery isolates. Six other brewing isolates were similar to ATCC 25249. The other 18 P. damnosus brewery isolates had unique patterns. Of the remaining brewing isolates, one was identified as P. parvulus, two were identified as P. acidilactici, and two were identified as unique Pediococcus species. The use of alternate restriction endonucleases indicated that PstI and PvuII could further differentiate some strains having identical EcoRI profiles. An acid-resistant P. damnosus isolate could be distinguished from non-acid-resistant varieties of the same species using PstI instead of EcoRI. 16S rRNA gene sequence analysis was compared to riboprinting for identifying pediococci. The complete 16S rRNA gene was PCR amplified and sequenced from seven brewery isolates and three ATCC references with distinctive riboprint patterns. The 16S rRNA gene sequences from six different brewery P. damnosus isolates were homologous with a high degree of similarity to the GenBank reference strain but were identical to each other and one ATCC strain with the exception of 1 bp in one strain. A slime-producing, beer spoilage isolate had 16S rRNA gene sequence homology to the P. acidilactici reference strain, in agreement with the riboprint data. Although 16S rRNA gene sequencing correctly identified the genus and species of the test Pediococcus isolates, riboprinting proved to be a better method for subspecies differentiation. (+info)
Blood glucose in intoxicated chronic alcoholics.
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Chronic alcoholics may present with hyperglycemia or hypoglycemia. Because alcohol induces glycogenolysis, chronic alcoholics usually have higher blood glucose values than do nonalcoholic subjects. In a prospective study of blood glucose concentration in 201 chronic alcoholics, blood alcohol concentration, sex, weight, type of beverage consumed and time since last eating were not generally associated with lower blood glucose values. The infrequency of hypoglycemia in ambulatory chronic alcoholics may reflect the relatively ready availability of hostels, detoxification centres and hospitals in large cities. It is, however, important to be aware of the possible occurrence of hypoglycemia in chronic alcoholics, particularly when community facilities for the chronic alcoholic are not available. (+info)
In vitro biotransformation of xanthohumol, a flavonoid from hops (Humulus lupulus), by rat liver microsomes.
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Xanthohumol (XN) is the major prenylated flavonoid of the female inflorescences (cones) of the hop plant (Humulus lupulus). It is also a constituent of beer, the major dietary source of prenylated flavonoids. Recent studies have suggested that XN may have potential cancer-chemopreventive activity, but little is known about its metabolism. We investigated the biotransformation of XN by rat liver microsomes. Three major polar metabolites were produced by liver microsomes from either untreated rats or phenobarbital-pretreated rats as detected by reverse-phase high-performance liquid chromatography analysis. Liver microsomes from isosafrole- and beta-naphthoflavone-pretreated rats formed another major nonpolar metabolite in addition to the three polar metabolites. As determined by liquid chromatography/mass spectrometry and (1)H NMR analyses, the three major polar microsomal metabolites of XN were tentatively identified as 1) 5"-isopropyl-5"-hydroxydihydrofurano[2",3":3',4']-2',4-dihydroxy-6'-methoxychalco ne; 2) 5"-(2"'-hydroxyisopropyl)-dihydrofurano[2",3":3',4']-2',4-dihydroxy-6'-methoxycha lcone; and 3) a derivative of XN with an additional hydroxyl function at the B ring. The nonpolar XN metabolite was identified as dehydrocycloxanthohumol. (+info)