Appl Biochem Biotechnol, 1999 Nov, 82(2), 127 - 34 The influence of inert solids on ethanol production by Saccharomyces cerevisiae; Prakasham RS et al.; The catalytic role of various inert solid supports on acceleration of alcohol fermentation by Saccharomyces cerevisiae was investigated . The enhanced rate of alcohol production was dependent on the nature of the support as well as on the amount used . Among all the tested supports, chitosan flakes showed the maximum yield of alcohol (93% of theoretical yield) . This higher rate of alcohol production was associated with the twofold increase in the activity of alcohol dehydrogenase over control . Our results suggest that the addition of a small fraction of solids in submerged fermentations to facilitate cell anchorage for enhanced metabolic activity is easier and more economical compared to cell immobilization processes. Curr Opin Biotechnol, 2000 Apr, 11(2), 187 - 98 Metabolic engineering applications to renewable resource utilization; Aristidou A et al.; Lignocellulosic materials containing cellulose, hemicellulose, and lignin are the most abundant renewable organic resource on earth . The utilization of renewable resources for energy and chemicals is expected to increase in the near future . The conversion of both cellulose (glucose) and hemicellulose (hexose and pentose) for the production of fuel ethanol is being studied intensively, with a view to developing a technically and economically viable bioprocess . Whereas the fermentation of glucose can be carried out efficiently, the bioconversion of the pentose fraction (xylose and arabinose, the main pentose sugars obtained on hydrolysis of hemicellulose), presents a challenge . A lot of attention has therefore been focused on genetically engineering strains that can efficiently utilize both glucose and pentoses, and convert them to useful compounds, such as ethanol . Metabolic strategies seek to generate efficient biocatalysts (bacteria and yeast) for the bioconversion of most hemicellulosic sugars to products that can be derived from the primary metabolism, such as ethanol . The metabolic engineering objectives so far have focused on higher yields, productivities and expanding the substrate and product spectra. Curr Opin Biotechnol, 2000 Apr, 11(2), 180 - 6 Mathematical modelling of metabolism; Gombert AK et al.; Mathematical models of the cellular metabolism have a special interest within biotechnology . Many different kinds of commercially important products are derived from the cell factory, and metabolic engineering can be applied to improve existing production processes, as well as to make new processes available . Both stoichiometric and kinetic models have been used to investigate the metabolism, which has resulted in defining the optimal fermentation conditions, as well as in directing the genetic changes to be introduced in order to obtain a good producer strain or cell line . With the increasing availability of genomic information and powerful analytical techniques, mathematical models also serve as a tool for understanding the cellular metabolism and physiology. J Agric Food Chem, 1998 Feb 16, 46(2), 783 - 787 Solid-State Production of Beneficial Fungi on Apple Processing Wastes Using Glucosamine as the Indicator of Growth; Zheng Z et al.; Three Trichoderma species, a Penicillium species, and a Rhizopus species were grown on apple pomace at 25 degrees C through solid-state fermentation . The effects of CaCO(3), water, and nitrogen sources on the growth of selected fungi on apple pomace were investigated . Soluble protein and glucosamine contents of fermented pomace were measured as the parameters of fungal growth . The maximum growth of all fungi was established on apple pomace supplemented with 0.05 g of CaCO(3), 2 mL of water, and 0.05 g of NH(4)NO(3) or 0.3 mL of fish protein hydrolysate per gram of pomace . The optimal water activity of the medium for fungal growth was 0.96 at 25 degrees C . This research has provided a clear indication for using glucosamine as a proper indicator of fungal growth in heterogeneous solid-state systems . It also shows potentials for bioconversion of apple processing wastes by beneficial fungi into valuable bioinoculants that are being targeted for agricultural and environmental applications. J Agric Food Chem, 1998 Feb 16, 46(2), 477 - 480 Determination of the (13)C Content of Glycerol Samples of Different Origin; Fronza G et al.; The average carbon isotope value (delta(13)C) of 63 samples of glycerol from over 30 different sources has been determined . The results indicate that it is possible to distinguish the glycerol obtained from the glycerides produced in plants following C-3 and C-4 carbon fixation pathways . The samples obtained from animal sources seem to reflect the composition of the material consumed, as well as that produced by sugar fermentation. J Agric Food Chem, 1998 Jan 19, 46(1), 202 - 205 Characterization of N-(Nitrosomethyl)urea in Nitrosated Fermented Fish Products; Deng D et al.; To characterize chemical carcinogens in acidic-nitrosated fish sauce sample, N-nitrosamides in the sample were separated by two kinds of reversed-phase HPLC columns, and with detection by photolysis-pyrolysis-thermal energy analyzer . A strong chromatographic peak at t(R) 12 or 4.5 min, same as that for N-(nitrosomethyl)urea (NMU), was obtained on PRP-1 or C(18) HPLC column from fish sauce sample with 10 mM trifluoroacetic acid as the basic mobile; acetonitrile, as organic modifier after the sample was nitrosated by 5 mmol/L of sodium nitrite (final concentration) at 37 degrees C and pH 2.0 for 1 h . No response above t(R) could be observed from the nitrosated sample in the detection system without photolysis . Such a peak could not be obtained from the unnitrosated fish sauce either . These results indicated that the component was NMU . Furthermore, this component, NMU, could also be detected in the nitrosated human gastric juice sample spiked with fish sauce . The formation of NMU in the sample was pH- and nitrite-dependent . This paper provides direct evidence that NMU formation could occur in fish sauce from the high-risk area for stomach cancer and in the fish sauce spiked human gastric juice during nitrosation under simulated gastric conditions. J Agric Food Chem, 1998 Jan 19, 46(1), 42 - 48 Relation between Fatty Acid Content and Its Evolution during Fermentation and Utilization of Free Amino Acids in Vacuum-Filtered Viura Must; Ayestaran B et al.; The activity of proteins that transport amino acids changes depending on the unsaturated residue which is introduced into the phospholipids of Saccharomycescerevisiae membrane . The aim of this study was to observe the influence of fatty acid content and its evolution during fermentation on the utilization of free amino acids in Vitis vinifera var . Viura must clarified by vacuum filtration . The results demonstrate that filtration of the must did not reduce the concentration of free amino acids, but it did reduce fatty acids, especially the unsaturateds . In the first half of fermentation (up to 50% sugar consumption), fatty acid utilization was different in each sample without involving an alteration in the uptake of amino acids . In the second half of fermentation (from 50% sugar consumption until the end of fermentation), the clarified sample had greater consumption of saturated fatty acids than unsaturated, in contrast to the control; this, along with other factors, produced a greater liberation of free amino acids in the filtered sample. Int J Syst Evol Microbiol, 2000 Nov, 50 Pt 6, 2013 - 20 Gluconacetobacter entanii sp . nov., isolated from submerged high-acid industrial vinegar fermentations; Schuller G et al.; Acetic acid bacteria have been isolated from submerged high-acid spirit vinegar fermentations in the Southern part of Germany . Four strains (LTH 4560T, LTH 4341, LTH 4551 and LTH 4637) were characterized in more detail and it was revealed that they have in common certain properties such as requirement of acetic acid, ethanol and glucose for growth, and no over-oxidation of acetate . Growth occurs only at total concentrations (sum of acetic acid and ethanol) exceeding 6.0% . A method for their preservation was developed . Comparative analysis of the 16S rRNA revealed sequence similarities of >99% between strain LTH 4560T and the type strains of the related species Gluconacetobacter hansenii . However, low levels of DNA relatedness (<41 %) were determined in DNA-DNA similarity studies . In addition, specific physiological characteristics permitted a clear identification of the strains within established species of acetic acid bacteria . The strains could also be differentiated on the basis of the distribution of IS element 1031 C within the chromosome . Based on these results, the new species Gluconacetobacter entanii sp . nov . is proposed for strain LTH 4560T ( = DSM 13536T) . A 16S-rRNA-targeted oligonucleotide probe was constructed that was specific for G . entanii, and the phylogenetic position of the new species was derived from a 16S-rRNA-based tree. Int J Syst Evol Microbiol, 2000 Nov, 50 Pt 6, 1981 - 7 Identification of acetic acid bacteria by RFLP of PCR-amplified 16S rDNA and 16S-23S rDNA intergenic spacer; Ruiz A et al.; DNA corresponding to 16S rDNA and the 165-23S rDNA intergenic spacer (ITS) from 22 reference strains of acetic acid bacteria, representing the diversity of the family Acetobacteraceae, and 24 indigenous acetic acid bacteria isolated from wine fermentations were analysed by PCR-RFLP . Frateuria aurantia LMG 1558T and Escherichia coli ATCC 11775T were included as outgroups . PCR-amplified products of about 1450 bp were obtained from the 16S rDNA of all the strains and products of between 675 and 800 bp were obtained from the 16S-23S rDNA ITS . PCR products were digested with 4-base-cutting restriction enzymes in order to evaluate the degree of polymorphism existing among these strains . Of the enzymes tested, Taql and Rsal were the most discriminatory and showed no intraspecific variations in the restriction patterns . Restriction analysis of the 16S rDNA with these enzymes is proposed as a rapid and reliable method to identify acetic acid bacteria at the level of genus and species (or related species group) and its applicability to identification of indigenous acetic acid bacteria was demonstrated . The same degree of distinction as that for the 16S rDNA analysis was obtained within reference strains of acetic acid bacteria by PCR-RFLP of the 16S-23S rDNA ITS . However, 16S-23S rDNA ITS restriction patterns of strains isolated from wine did not match those of any of the reference strains . Thus, PCR-RFLP of the 16S-23S rDNA ITS is not a useful method to identify isolates of acetic acid bacteria at the species level, although it may be an adequate method to detect intraspecific differentiation. Oral Microbiol Immunol, 2000 Jun, 15(3), 188 - 95 Glucose metabolism by Prevotella intermedia and Prevotella nigrescens; Takahashi N et al.; Glucose metabolism by Prevotella intermedia and Prevotella nigrescens were investigated . Glucose increased the anaerobic growth of these bacteria and promoted the accumulation of intracellular polysaccharide . The polysaccharide was confirmed to be glycogen-like glucan by the absorption spectrum of iodinepolysaccharide complex and the sugar composition . The washed cells consumed glucose anaerobically and converted a part of glucose into the metabolic end-products acetate, formate and succinate . The rest of glucose was confirmed to be accumulated as intracellular polysaccharide . The cells grown in the presence of glucose produced acetate, formate and succinate without exogenous glucose along with the consumption of intracellular polysaccharide . The metabolism of glucose and intracellular polysaccharide required bicarbonate . Prevotella cells had hexokinase and a set of the usual enzymes of the Embden-Meyerhof-Parnas pathway except that phosphofructokinase was pyrophosphate-dependent . A series of enzymes, including phosphoenolpyruvate carboxylase, phosphoenolpyruvate carboxykinase, malate dehydrogenase, fumarase and fumarate reductase, was found for succinate formation . Another series of enzymes, pyruvate oxidoreductase, pyruvate formate-lyase, phosphotransacetylase and acetate kinase was found for acetate and formate formation . Glucose 1,6-bisphosphate-dependent phosphoglucomutase and fructose 1,6-bisphosphate-activated UDP-glucose pyrophosphorylase were detected for glycogen synthesis, while glycogen phosphorylase was for glycogen degradation . The capacity of intracellular polysaccharide formation in addition to glucose fermentation could be advantageous for survival in the supragingival area as well as in the subgingival area. Mol Cell Biol, 2001 Feb, 21(3), 916 - 27 Global and specific translational regulation in the genomic response of Saccharomyces cerevisiae to a rapid transfer from a fermentable to a nonfermentable carbon source; Kuhn KM et al.; The global gene expression program that accompanies the adaptation of Saccharomyces cerevisiae to an abrupt transfer from a fermentable to a nonfermentable carbon source was characterized by using a cDNA microarray to monitor the relative abundances and polysomal distributions of mRNAs . Features of the program included a transient reduction in global translational activity and a severe decrease in polysome size of transcripts encoding ribosomal proteins . While the overall translation initiation of newly synthesized and preexisting mRNAs was generally repressed after the carbon source shift, the mRNA encoded by YPL250C was an exception in that it selectively mobilized into polysomes, although its relative abundance remained unchanged . In addition, splicing of HAC1 transcripts, which has previously been reported to occur during accumulation of unfolded proteins in the endoplasmic reticulum, was observed after the carbon shift . This finding suggests that the nonconventional splicing complex, composed of the kinase-endonuclease Ire1p and the tRNA ligase Rlg1p, was activated . While spliced HAC1 transcripts mobilized into polysomes, the vast majority of unspliced HAC1 RNA accumulated in nonpolysomal fractions before and after the carbon source shift, indicating that translation of unspliced HAC1 RNA is blocked at the translation initiation step, in addition to the previously reported elongation step . These findings reveal that S . cerevisiae reacts to the carbon source shift with a remarkable variety of responses, including translational regulation of specific mRNAs and activation of specific enzymes involved in a nonconventional splicing mechanism. Vitam Horm, 2001, 61, 51 - 101 Biosynthesis of biotin and lipoic acid; Marquet A et al.; The genetics and mechanistic enzymology of biotin biosynthesis have been the subject of much investigation in the last decade, owing to the interest for biotin production by fermentation, on the one hand, and for the design of inhibitors with potential herbicidal properties, on the other hand . Four enzymes are involved in the synthesis of biotin from its two precursors, alanine and pimeloyl-CoA . They are now well-characterized and the X-ray structures of the first three have been published . 8-Amino-7-oxopelargonic acid synthase is a pyridoxal 5'-phosphate (PLP) enzyme, very similar to other acyl-CoA alpha-oxoamine synthases, and its detailed mechanism has been determined . The origin of its specific substrate, pimeloyl-CoA, however, is not completely established . It could be produced by a modified fatty acid pathway involving a malonyl thioester as the starter . 7,8-Diaminopelargonic acid (DAPA) aminotransferase, although sharing sequence and folding homologies with other transaminases, is unique as it uses S-adenosylmethionine (AdoMet) as the NH2 donor . The mechanism of dethiobiotin synthethase is also now well understood . It catalyzes the formation of the ureido ring via a DAPA carbamate activated with ATP . On the other hand, the mechanism of the last enzyme, biotin synthase, which has long raised a very puzzling problem, is only starting to be unraveled and appears indeed to be very complex . Biotin synthase belongs to the family of AdoMet-dependent enzymes that reductively cleave AdoMet into a deoxyadenosyl radical, and it is responsible for the homolytic cleavage of C-H bonds . A first radical formed on dethiobiotin is trapped by the sulfur donor, which was found to be the iron-sulfur (Fe-S) center contained in the enzyme, and cyclization follows in a second step . Two important features come from these results: (1) a new role for an Fe-S center has been revealed, and (2) biotin synthase is not only a catalyst but also a substrate for the reaction . Lipoate synthase, which catalyzes the formation of two C-S bonds from octanoic acid, has a very high sequence similarity with biotin synthase . Although no in vitro enzymology has been carried out with lipoate synthase, the sequence homology as well as the results of in vivo studies support the conclusion that both enzymes are strongly mechanistically related. FEMS Microbiol Rev, 2001 Jan, 25(1), 15 - 37 Stoichiometry and compartmentation of NADH metabolism in Saccharomyces cerevisiae; Bakker BM et al.; In Saccharomyces cerevisiae, reduction of NAD(+) to NADH occurs in dissimilatory as well as in assimilatory reactions . This review discusses mechanisms for reoxidation of NADH in this yeast, with special emphasis on the metabolic compartmentation that occurs as a consequence of the impermeability of the mitochondrial inner membrane for NADH and NAD(+) . At least five mechanisms of NADH reoxidation exist in S . cerevisiae . These are: (1) alcoholic fermentation; (2) glycerol production; (3) respiration of cytosolic NADH via external mitochondrial NADH dehydrogenases; (4) respiration of cytosolic NADH via the glycerol-3-phosphate shuttle; and (5) oxidation of intramitochondrial NADH via a mitochondrial 'internal' NADH dehydrogenase . Furthermore, in vivo evidence indicates that NADH redox equivalents can be shuttled across the mitochondrial inner membrane by an ethanol-acetaldehyde shuttle . Several other redox-shuttle mechanisms might occur in S . cerevisiae, including a malate-oxaloacetate shuttle, a malate-aspartate shuttle and a malate-pyruvate shuttle . Although key enzymes and transporters for these shuttles are present, there is as yet no consistent evidence for their in vivo activity . Activity of several other shuttles, including the malate-citrate and fatty acid shuttles, can be ruled out based on the absence of key enzymes or transporters . Quantitative physiological analysis of defined mutants has been important in identifying several parallel pathways for reoxidation of cytosolic and intramitochondrial NADH . The major challenge that lies ahead is to elucidate the physiological function of parallel pathways for NADH oxidation in wild-type cells, both under steady-state and transient-state conditions . This requires the development of techniques for accurate measurement of intracellular metabolite concentrations in separate metabolic compartments. FEBS Lett, 2000 Dec 22, 487(1), 56 - 60 Genomic exploration of the hemiascomycetous yeasts: 9 . Saccharomyces kluyveri; Neuveglise C et al.; The genome of Saccharomyces kluyveri was explored through 2528 random sequence tags with an average length of 981 bp . The complete nuclear ribosomal DNA unit was found to be 8656 bp in length . Sequences homologous to retroelements of the gypsy and copia types were identified as well as numerous solo long terminal repeats . We identified at least 1406 genes homologous to Saccharomyces cerevisiae open reading frames, with on average 58.1% and 72.4% amino acid identity and similarity, respectively . In addition, by comparison with completely sequenced genomes and the SwissProt database, we found 27 novel S . kluyveri genes . Most of these genes belong to pathways or have functions absent from S . cerevisiae, such as the catabolic pathway of purines or pyrimidines, melibiose fermentation, sorbitol utilization, or degradation of pollutants . The sequences are deposited in EMBL under the accession numbers AL404849-AL407376. Appl Microbiol Biotechnol, 2000 Dec, 54(6), 814 - 8 Residual fructose and osmolality affect the levels of pneumocandins B0 and C0 produced by Glarea lozoyensis; Connors N et al.; A high total pneumocandin titer (B0 + C0) with a low percentage of the structural isomer pneumocandin C0 was achieved by carrying out fermentations of Glarea lozoyensis at a high residual fructose concentration (125 g/l initial) . When the fermentation was carried out at a low residual fructose concentration (40 g/l initial), pneumocandin production increased by 34% . However, a disproportionate increase in the level of pneumocandin C0 synthesized (250% increase vs 30% increase for pneumocandin B0) was observed . Midcycle addition of 150 mM NaCl or 116 mM Na2SO4 to low residual fructose fermentations returned the titer and isomer levels to those seen for the high residual fructose fermentation . The increase in pneumocandin C0 synthesis under low residual fructose conditions appears to be linked to the increase in the synthesis of trans-4 hydroxyproline, with the synthesis of trans-3 hydroxyproline remaining unaffected . This suggests that the formation of pneumocandin C0 is the result of a misincorporation of trans-4 hydroxyproline instead of trans-3 hydroxyproline by the pneumocandin peptide synthetase, and that the amount of trans-4 hydroxyproline formed dictates the frequency of this misincorporation. Appl Microbiol Biotechnol, 2000 Dec, 54(6), 786 - 91 The gene encoding gamma-actin from the cephalosporin producer Acremonium chrysogenum; Diez B et al.; The nucleotide sequence of a 3240-bp genomic fragment including the gamma-actin-encoding gene from Acremonium chrysogenum has been determined, showing an open reading frame of 1691 bp, interrupted by five introns with fungal consensus splice-site junctions . The untranslated regions of the actA gene contain a consensus TATA box, a CCAAT motif, pyrimidine stretches and the polyadenylation sequence AATAA . The predicted protein (375 amino acids) revealed high identity to gamma-actins from fungi (> 90%) . Gene phylogenies constructed using DNA and protein sequences support the grouping of A . chrysogenum actin close to those from the majority of the filamentous fungi . The actA gene is present as a single copy in the genome of A . chrysogenum; and its expression level, opposite to pcbC and cefEF cephalosporin biosynthetic genes, was steady during cephalosporin fermentation, showing a single 1.4-kb transcript. Appl Microbiol Biotechnol, 2000 Dec, 54(6), 772 - 7 Overexpression and lack of degradation of thaumatin in an aspergillopepsin A-defective mutant of Aspergillus awamori containing an insertion in the pepA gene; Moralejo FJ et al.; A gene encoding the sweet-tasting protein thaumatin (tha) with optimized codon usage was expressed in Aspergillus awamori . Mutants of A . awamori with reduced proteolytic activity were isolated . One of these mutants, named lpr66, contained an insertion of about 200 bp in the pepA gene, resulting in an inactive aspergillopepsin A . In vitro thaumatin degradation tests confirmed that culture broths of mutant lpr66 showed only a small thaumatin-degrading activity . A . awamori lpr66 has been used as host strain for thaumatin expression cassettes containing the tha gene under the control of either the cahB (cephalosporin acetylhydrolase) promoter of Acremonium chrysogenum or the gdhA (glutamate dehydrogenase) promoter of Aspergillus awamori . Residual proteolytic activities were repressed by using a mixture of glucose and sucrose as carbon sources and L-asparagine as nitrogen source . Degradation of thaumatin by acidic proteases was prevented by maintaining the pH value at 6.2 in the fermentor . Expression of cassettes containing the gdhA promoter was optimal in ammonium sulfate as nitrogen source, whereas transformants expressing the tha gene from the cahB promoter yielded higher thaumatin levels using L-asparagine as nitrogen source . Under optimal fermentation conditions, yields of 105 mg thaumatin/l were obtained, thus making this fermentation a process of industrial interest. Appl Microbiol Biotechnol, 2000 Dec, 54(6), 764 - 71 Biological upgrading of wheat straw through solid-state fermentation with Streptomyces cyaneus; Berrocal M et al.; The biological upgrading of wheat straw with Streptomyces cyaneus was examined through the analysis of chemical and structural changes of the transformed substrate during solid-state fermentation . Analysis of enzymes produced during the growth of S . cyaneus showed that phenol oxidase was the predominant enzyme . The reduction in Klason lignin content (16.4%) in the transformed substrate indicated the ability of this strain to delignify lignocellulose residues and suggests a role for phenol oxidase in the bacterial delignification process . Microscopic examination of the transformed substrate showed that the initial attack occurred at the less lignified cell walls (phloem and parenchyma), while xylem and sclerenchyma were slowly degraded . The pattern of degradation of sclerenchymatic tissues by S . cyaneus showed delamination between primary and secondary walls and between S1 and S2 due to partial removal of lignin . In the later stages of the decay a disorganization of the secondary walls was detected on account of fibrillation of this layer . A comparison of the properties of the pulp from wheat straw transformed by S . cyaneus with untreated wheat straw showed that pretreatment improved the characteristics that determine the quality of pulp . This was indicated by an increase in pulp brightness and by a decrease in the kappa number . These changes occurred without significantly affecting the viscosity, a measure of the quality of the cellulose fibres . These results support the potential application of this organism or its oxidative enzymes in biopulping. Am J Gastroenterol, 2000 Dec, 95(12), 3374 - 82 The effects of alcohol consumption upon the gastrointestinal tract; Bujanda L; Regardless of the type and dose of beverage involved, alcohol facilitates the development of gastroesophageal reflux disease by reducing the pressure of the lower esophageal sphincter and esophageal motility . Fermented and nondistilled alcoholic beverages increase gastrin levels and acid secretion . Succinic and maleic acid contained in certain alcoholic drinks also stimulate acid secretion . Low alcohol doses accelerate gastric emptying, whereas high doses delay emptying and slow bowel motility . Alcohol facilitates the development of superficial gastritis and chronic atrophic gastritis--though it has not been shown to cause peptic ulcer . Alcoholic beverages, fundamentally wine, have important bactericidal effects upon Helicobacter pylori and enteropathogenic bacteria . The main alcohol-related intestinal alterations are diarrhea and malabsorption, with recovery after restoring a normal diet . Alcohol facilitates the development of oropharyngeal, esophageal, gastric, and colon cancer . Initial research suggests that wine may be comparatively less carcinogenic. Pharmacoeconomics, 2000, 18 Suppl 1, 15 - 20 Post-modern drug evaluation . The deconstruction of evidence-based regulation; Avorn J; Traditionally in medicine, nearly all prescribing decisions were made by the treating physician . The patient had relatively little input and hardly any access to alternative sources of information bearing on that decision; the cost of the prescription was covered by the patient or by an insurer, and neither was likely to provide any feedback to the physician to shape his or her decision . Now, all that has changed . Beginning with the consumerist movement of recent decades and culminating in the explosion of health-related information on the Internet, patients are increasingly vocal participants in the prescribing decision, on both clinical and economic grounds . Payers have become participants as well, and increasingly seek to influence prescribing decisions in the light of their own economic imperatives . Added to all these cross-currents is an additional wild card: the proliferation of 'alternative medicines,' 'nutraceuticals' and other nostrums that society has placed beyond the reach of the evidence-based discourse and regulations that govern conventional drug therapy . In a country where patients struggle to cover the cost of prescription therapies proven both safe and effective in rigorous clinical trials, billions of dollars per year are spent on alternative treatments in the US, unencumbered by concerns about whether they actually work or that they might be toxic . While these patterns of communication, education, disinformation and economic influence are much more chaotic than those that prevailed in the 'good old days,' this very ferment may also present opportunities for improvement of rational pharmacotherapy and public health . This paper briefly outlines the above changes in patterns of communication and influence as they relate to medication use in today's industrialised world (particularly the US), and suggests both hopeful and terrifying scenarios describing where these trends might lead in the coming decade. Biochem, Eng . J. . 2001 Jan, 7(1), 7 - 16 Modeling of antibiotics production in magneto three-phase airlift fermenter; Al-Qodah Z et al.; A mathematical model is developed to describe the performance of a three-phase airlift reactor utilizing a transverse magnetic field . The model is based on the complete mixing model for the bulk of liquid phase and on the Michaelis-Menten kinetics . The model equations are solved by the explicit finite difference method from transient to steady state conditions . The results of the numerical simulation indicate that the magnetic field increases the degree of bioconversion . The mathematical model is experimentally verified in a three-phase airlift reactor with P . chrysogenum immobilized on magnetic beads . The experimental results are well described by the developed model when the reactor operates in the stabilized regime . At relatively high magnetic field intensities a certain discrepancy in the model solution was observed when the model over estimates the product concentration. J Org Chem, 2000 Dec 29, 65(26), 9039 - 46 Novel bioactive breviane spiroditerpenoids from Penicillium brevicompactum Dierckx; Macias FA et al.; The structures of four new, naturally occurring bioactive spiroditerpenoids, (+)-breviones B, C, D, and E, potential allelopathic agents, have been determined from extracts of semisolid fermented Penicillium brevicompactum Dierckx . The structures display the novel breviane spiroditerpenoid skeleton . Structure elucidation was performed by chemical transformations and by homo- and heteronuclear 2D-NMR spectral data . On the basis of combined studies of the theoretical conformations and NOEDIFF data, their relative stereochemistry is proposed . A mixed biogenesis for this novel family of spiroditerpenoids is tendered . The levels of activity shown by breviones B, C, and E in the etiolated wheat coleoptiles bioassay, especially breviones E (100% inhibition) and C (80% inhibition) both at 10(-4) M, suggest them as lead compounds for new agrochemicals. Rev Argent Microbiol, 2000 Oct-Dec, 32(4), 185 - 9 {Influence of amaranth on the production of alpha-amylase using Aspergillus niger NRRL 3112}; Mariani DD et al.; In this paper the influence of the amaranth seed meal and the aeration conditions on the alpha-amylase production by Aspergillus niger NRRL 3112 were studied . The assays of selection of culture medium were carried out in a rotary shaker at 250 rpm and 2.5 cm stroke . The aeration conditions were studied in a mechanically stirred fermentor New Brunswick type . A concentration of alpha-amylase of 2750 U.Dun/ml was achieved at 120 h with a dry weight of 8.0 g/l, using a base medium with 5.0 g/l Amaranthus cruentus seed meal . In the experiment performed in a New Brunswick fermentor, the highest value was 2806 U.Dun/ml . This result was obtained after 120 h, operating at 300 rpm and an airflow of 1 l/l . min . in a limited dissolved oxygen concentration . It was determined that the increase in the agitation rate was not favorable to the enzyme production, despite that an increase was verified in the dissolved oxygen . The morphology of the microorganism, in long and ramified hyphae, was the critical factor to obtain higher levels of alpha-amylase. J Pediatr Gastroenterol Nutr, 2000 Nov, 31(5), 503 - 7 Partially hydrolyzed guar gum-supplemented oral rehydration solution in the treatment of acute diarrhea in children; Alam NH et al.; BACKGROUND: Partially hydrolyzed guar gum (Benefiber; Novartis Nutrition, Minneapolis, MN, U.S.A.) is fermented by colonic bacteria liberating short-chain fatty acids (SCFAs), which accelerate colonic absorption of salt and water . The purpose of this study was to evaluate the effect of Benefiber (BF)-supplemented World Health Organization Oral Rehydration Solution (WHO ORS) in the treatment of acute noncholera diarrhea in children . METHODS: A double-blind, randomized, controlled clinical trial was performed at ICDDR,B in 150 male children aged 4 to 18 months who had watery diarrhea of less than 48 hours' duration . After admission, children were assigned to receive either WHO ORS or BF-supplemented WHO ORS until recovery . Major outcome measures, such as duration of diarrhea and amount of stool output, were compared between the treatment groups . RESULTS: Patients receiving BF-supplemented WHO ORS had significantly reduced duration of diarrhea compared with the control group (mean +/- SD, 74 +/- 37 vs . 90 +/- 50 hours, P = 0.03) . Survival analysis for duration of diarrhea also showed a reduction the BF-supplemented WHO ORS-treated group (P = 0.025, log rank test) . There was also less stool output daily from days 2 through 7 in the patients treated with BF-supplemented WHO ORS compared with that in the children treated with WHO ORS; the reduction was significant on day 7 only . CONCLUSION: Benefiber added to standard WHO ORS substantially reduces the duration of diarrhea and modestly reduced stool output in acute noncholera diarrhea in young children, indicating its potential as a new antidiarrheal therapy for acute diarrhea in children. Can J Microbiol, 2000 Dec, 46(12), 1096 - 100 Carbon source-dependent transcriptional regulation of the mitochondrial glycerol-3-phosphate dehydrogenase gene, GUT2, from Saccharomyces cerevisiae; Grauslund M et al.; Cytosolic glycerol kinase (Gut1p) and mitochondrial glycerol-3-phosphate dehydrogenase (Gut2p) constitute the glycerol utilization pathway in Saccharomyces cerevisiae . Transcriptional analysis of the GUT2 gene showed that it was repressed by glucose and derepressed on the non-fermentable carbon sources, glycerol, lactate and ethanol . Derepression of GUT2 requires the protein kinase Snflp as well as the heteromeric protein complex, Hap2/3/4/5, and its putative DNA-binding site (UASHAP) located in the promoter region . Furthermore, glucose repression of GUT2 requires the negative regulator, Opi1p. J Radiat Res (Tokyo), 2000 Oct, 41 Suppl, 53 - 62 A case-control study of nasopharyngeal carcinoma in the high background radiation areas of Yangjiang, China; Zou J et al.; The main purposes of this study were to identify the major determinants of nasopharyngeal carcinoma (NPC) in the high-background radiation areas (HBRA) in Yangjiang, China and to evaluate their potential confounding effects on the NPC risk associated with exposure to high background radiation . A matched case-control study was conducted using those who died of NPC during the period 1987-1995 . Two controls were randomly selected for each case from those who died from causes other than malignancies and external causes . Cases and their controls were matched with respect to sex and the years of birth and death (+/- 5 years) . Study subjects' next-of-kin were interviewed using a standardized questionnaire to collect information on socioeconomic status, dietary habits, tobacco smoking and alcohol consumption, disease history, pesticide use, medical X-ray exposure, the family history of NPC and so on . We succeeded in interviewing 97 cases and 192 controls . Univariate conditional logistic regression analysis showed that NPC risk was associated with the consumption of salted fish, homemade pickles, and fermented soy beans, education levels, the history of chronic rhinitis, and the family history of NPC . Multivariate conditional logistic regression analysis revealed that education levels (Odds ratio (OR) for middle school or higher levels vs . no school education = 3.8, 95% CI = 1.2 to 11.8), salted fish intake (OR = 3.2, 95% CI = 1.7 to 6.1), the history of chronic rhinitis (OR = 3.6, 95% CI = 1.3 to 10.1), and the family history of NPC (OR = 14.2, 95% CI = 2.7 to 73.4) were independent risk factors of NPC . Tobacco smoking (OR = 1.2, 95% CI = 0.7 to 2.1), and alcohol consumption (OR = 0.9, 95% CI = 0.5 to 1.9) were not significantly related to NPC risk . The ORs of NPC risk comparing HBRA and a nearby control area before and after adjustment for the major risk determinants identified in the present study were 0.86 (95% CI = 0.50 to 1.50) and 0.87 (95% CI = 0.45 to 1.67), respectively . Salted fish intake was a strong risk factor of NPC . Education, the history of chronic rhinitis and the family history of NPC were also related to NPC risk . The exposure to high background radiation in HBRA of Yangjiang was not related to NPC risk with or without the adjustment for those major risk determinants of NPC. J Nat Prod, 2000 Dec, 63(12), 1709 - 11 Microbial transformation of the eudesmane sesquiterpene plectranthone; Orabi KY; Microbial transformation studies of plectranthone (1) have revealed that it was metabolized by a number of microorganisms . Using a standard two-stage fermentation technique, Beauvaria bassiana (ATCC 7159) produced five metabolites, 2-6 . These metabolites were characterized on the basis of spectral data. Reprod Nutr Dev, 2000 Sep-Oct, 40(5), 431 - 40 Effects of Lavandula officinalis and Equisetum arvense dry extracts and isoquercitrin on the fermentation of diets varying in forage contents by rumen microorganisms in batch culture; Broudiscou LP et al.; The short-term actions of Lavandula officinalis and Equisetum arvense dry extracts, and of isoquercitrin, flavonoid present in Equisetum arvense, on in vitro fermentation by rumen microbes were studied in batch culture . The orchard grass hay:barley ratios in the three experimental diets were 100:0, 75:25, 50:50 on a DM basis . The production rates of all volatile fatty acids except isobutyrate were strongly influenced by the composition of the diet and to a lesser extent, by plant extracts, with significant interactions between both factors . When hay was the only substrate, the addition of L . officinalis and E . arvense enhanced the fermentation rate by 50%, through an increased release of acetate and propionate . On the contrary, with the two other diets, the fermentation rate was strongly lowered by isoquercitrin . Gas outputs were not significantly influenced by plant extracts. Toxicon, 2001 Jun, 39(6), 837 - 41 Determination of destruxins, cyclic peptide toxins, produced by different strains of Metarhizium anisopliae and their mutants induced by ethyl methane sulfonate and ultraviolet using HPLC method; Hsiao YM et al.; Metarhizium anisopliae produces a family of cyclic peptide toxins, destruxins (DTXs), which exhibit various insecticidal activity . Four major DTXs have been separated by HPLC and identified by the liquid chromatography electrospray mass spectrometry (LC-ESI-MS) methods . Strain F061 of M . anisopliae produced large amounts of (DTXs), especially DTX-A (12.84+/-0.04 microg/ml), DTX-B (66.89+/-2.57 microg/ml) and DMDB (1.41+/-0.13 microg/ml) . High levels of DTX-E (4.19+/-0.13 microg/ml) were produced by strain F007 of M . anisopliae . The results of our studies also showed that either ethyl methane sulfonate (EMS) or ultraviolet (UV) can significantly increase the production of DTXs . Mutant 61E-9 produced high levels of DTX-A (30.05+/-1.97 microg/ml), DTX-B (110.37+/-10.02 microg/ml) and DMDB (8.30+/-0.45 microg/ml) . High levels of DTX-E (20.59+/-2.65 microg/ml) were produced by mutant 7E-3 . Both mutant strains are suitable for industrial fermentation processes and possess a wide range of potential applications in the area of metabolic toxin production. FEMS Microbiol Ecol, 2001 Jan, 34(3), 181 - 186 Iron metabolism in anoxic environments at near neutral pH; Straub KL et al.; Anaerobic dissimilatory ferric iron-reducing and ferrous iron-oxidizing bacteria gain energy through reduction or oxidation of iron minerals and presumably play an important role in catalyzing iron transformations in anoxic environments . Numerous ferric iron-reducing bacteria have been isolated from a great diversity of anoxic environments, including sediments, soils, deep terrestrial subsurfaces, and hot springs . In contrast, only few ferrous iron-oxidizing bacteria are known so far . At neutral pH, iron minerals are barely soluble, and the mechanisms of electron transfer to or from iron minerals are still only poorly understood . In natural habitats, humic substances may act as electron carriers for ferric iron-reducing bacteria . Also fermenting bacteria were shown to channel electrons to ferric iron via humic acids . Whether quinones or cytochromes released from cells act as electron transfer components in ferric iron reduction is still a matter of debate . Anaerobic ferrous iron-oxidizing phototrophic bacteria, on the other hand, appear to excrete complexing agents to prevent precipitation of ferric iron oxides at their cell surfaces . The present review evaluates recent findings on the physiology of ferric iron-reducing and ferrous iron-oxidizing bacteria with respect to their relevance to microbial iron transformations in nature. Biotechnol Bioeng, 2001 Feb 5, 72(3), 269 - 77 Separation of lactic acid-producing bacteria from fermentation broth using a ceramic microfiltration membrane with constant permeate flow; Persson A et al.; The influence of several operating parameters on the critical flux in the separation of lactic acid-producing bacteria from fermentation broth was studied using a ceramic microfiltration membrane equipped with a permeate pump . The operating parameters studied were crossflow velocity over the membrane, bacterial cell concentration, protein concentration, and pH . The influence of the isoelectric point (IEP) of the membrane was also investigated . In the interval studied (5.3-10.8 m/s), the crossflow velocity had a marked effect on the critical flux . When the crossflow velocity was increased the critical flux also increased . The bacterial cells were retained by the membrane and the concentration of bacterial cells did not affect the critical flux in the interval studied (1.1-3.1 g/L) . The critical flux decreased when the protein concentration was increased . It was found that the protein was adsorbed on the membrane surface and protein retention occurred even though the conditions were such that no filter cake was present on the membrane surface . When the pH of the medium was lowered from 6 to 5 (and then further to 4) the critical flux decreased from 76 L/m(2)h to zero at both pH 5 and pH 4 . This was found to be due to the fact that the lowering in pH had affected the physiology of the bacterial cells so that the bacteria tended to adhere to the membrane and to each other . The critical flux, for wheat flour hydrolysate without particles, was much lower (28 L/m(2)h) when using a membrane with an IEP of 5.5 than the critical flux of a membrane with an IEP at pH 7 (96 L/m(2)h) . This was found to be due to an increased affinity of the bacteria for the membrane with the lower IEP . Appl Environ Microbiol, 2001 Jan, 67(1), 377 - 86 Use of direct-infusion electrospray mass spectrometry to guide empirical development of improved conditions for expression of secondary metabolites from actinomycetes; Zahn JA et al.; A major barrier in the discovery of new secondary metabolites from microorganisms is the difficulty of distinguishing the minor fraction of productive cultures from the majority of unproductive cultures and growth conditions . In this study, a rapid, direct-infusion electrospray mass spectrometry (ES-MS) technique was used to identify chemical differences that occurred in the expression of secondary metabolites by 44 actinomycetes cultivated under six different fermentation conditions . Samples from actinomycete fermentations were prepared by solid-phase extraction, analyzed by ES-MS, and ranked according to a chemical productivity index based on the total number and relative intensity of ions present in each sample . The actinomycete cultures were tested for chemical productivity following treatments that included nutritional manipulations, autoregulator additions, and different agitation speeds and incubation temperatures . Evaluation of the ES-MS data from submerged and solid-state fermentations by paired t test analyses showed that solid-state growth significantly altered the chemical profiles of extracts from 75% of the actinomycetes evaluated . Parallel analysis of the same extracts by high-performance liquid chromatography-ES-MS-evaporative light scattering showed that the chemical differences detected by the ES-MS method were associated with growth condition-dependent changes in the yield of secondary metabolites . Our results indicate that the high-throughput ES-MS method is useful for identification of fermentation conditions that enhance expression of secondary metabolites from actinomycetes. Appl Environ Microbiol, 2001 Jan, 67(1), 371 - 6 Rapid method to estimate the presence of secondary metabolites in microbial extracts; Higgs RE et al.; Screening microbial secondary metabolites is an established method to identify novel biologically active molecules . Preparation of biological screening samples from microbial fermentation extracts requires growth conditions that promote synthesis of secondary metabolites and extraction procedures that capture the secondary metabolites produced . High-performance liquid chromatography (HPLC) analysis of fermentation extracts can be used to estimate the number of secondary metabolites produced by microorganisms under various growth conditions but is slow . In this study we report on a rapid (approximately 1 min per assay) surrogate measure of secondary metabolite production based on a metabolite productivity index computed from the electrospray mass spectra of samples injected directly into a spectrometer . This surrogate measure of productivity was shown to correlate with an HPLC measure of productivity with a coefficient of 0.78 for a test set of extracts from 43 actinomycetes . This rapid measure of secondary metabolite productivity may be used to identify improved cultivation and extraction conditions by analyzing and ranking large sets of extracts . The same methods may also be used to survey large collections of extracts to identify subsets of highly productive organisms for biological screening or additional study. Appl Environ Microbiol, 2001 Jan, 67(1), 148 - 54 Mutation of the ptsG gene results in increased production of succinate in fermentation of glucose by Escherichia coli; Chatterjee R et al.; Escherichia coli NZN111 is blocked in the ability to grow fermentatively on glucose but gave rise spontaneously to a mutant that had this ability . The mutant carries out a balanced fermentation of glucose to give approximately 1 mol of succinate, 0 . 5 mol of acetate, and 0.5 mol of ethanol per mol of glucose . The causative mutation was mapped to the ptsG gene, which encodes the membrane-bound, glucose-specific permease of the phosphotransferase system, protein EIICB(glc) . Replacement of the chromosomal ptsG gene with an insertionally inactivated form also restored growth on glucose and resulted in the same distribution of fermentation products . The physiological characteristics of the spontaneous and null mutants were consistent with loss of function of the ptsG gene product; the mutants possessed greatly reduced glucose phosphotransferase activity and lacked normal glucose repression . Introduction of the null mutant into strains not blocked in the ability to ferment glucose also increased succinate production in those strains . This phenomenon was widespread, occurring in different lineages of E . coli, including E . coli B. Curr Microbiol, 2001 Feb, 42(2), 117 - 21 Structural and phylogenetic analysis of the gamma-actin encoding gene from the penicillin-producing fungus Penicillium chrysogenum; Diez B et al.; The nucleotide sequence of a 2994-bp genomic fragment, including the gamma-actin encoding gene from Penicillium chrysogenum, has been determined, showing an open reading frame (ORF) of 1756 bp interrupted by five introns with fungal consensus splice-site junctions . The 5' untranslated region contains a consensus TATA box, five CAAT motifs, and two large pyrimidine stretches . The predicted protein (375 amino acids) revealed high identity to gamma-actins from fungi (>90%), and gene phylogenies support the grouping of P . chrysogenum actin close to those from the majority of the filamentous fungi . The actA gene is present as a single copy in the genome of P . chrysogenum, and its expression is constitutive during penicillin fermentation, showing a single 1.4-kb transcript. J Antibiot (Tokyo), 2000 Oct, 53(10), 1130 - 6 Migrastatin, a new inhibitor of tumor cell migration from Streptomyces sp . MK929-43F1 . Taxonomy, fermentation, isolation and biological activities; Nakae K et al.; A new compound, migrastatin, was isolated from a cultured broth of Streptomyces sp . MK929-43F1, as an inhibitor of tumor cell migration . It was purified by column chromatographies on silica gel and Sephadex LH-20 and HPLC . Migrastatin has the molecular formula of C27H39NO7 consisting of 14-membered macrolide and glutarimide moiety . It inhibited spontaneous migration of human esophageal cancer EC17 cells . Migration inhibitory activity of migrastatin was not dependent on cytotoxicity or inhibition of protein synthesis. Oncol Res, 2000, 12(2), 83 - 95 Apoptosis cascade proteins are regulated in vivo by high intracolonic butyrate concentration: correlation with colon cancer inhibition; Avivi-Green C et al.; The present study was aimed at evaluating the effect of high intracolonic butyrate concentrations, either through fermentation of a soluble fiber-enriched diet or via intracolonic butyrate instillation, on colon cancer in a chemically induced (dimethylhydrazine) rat model . The effects were tested in four groups of dimethylhydrazine-treated rats: (i) rats fed a standard diet, (ii) rats fed a diet enriched with 15% citrus pectin, a soluble fiber that ferments and produces a high concentration of intracolonic butyrate, (iii) rats fed a standard diet and intrarectally instilled with a sodium butyrate solution (50 mM), (iv) rats fed a standard diet and intrarectally instilled with sodium butyrate vehicle solution (100 mM NaCl) . The apoptotic index in the distal colon of rats fed pectin was higher than in colonic tissue from rats fed a standard diet . The expression of caspase-1, a cysteine protease implicated in the regulation of programmed cell death, as detected by both Northern and Western analysis, showed the highest mRNA and protein levels in colonic tissue from rats intrarectally instilled with butyrate . Immunohistology confirmed the Western blot findings . Expression of the cleaved poly(ADP-ribose) polymerase product, a downstream nuclear substrate for caspase-3 in the apoptotic pathway, was elevated in both the pectin-fed and butyrate-instilled groups . Expression of the antiapoptotic protein Bcl-2 was significantly reduced following pectin feeding as well as butyrate instillation . The highest expression of Bcl-2 was observed in tumor tissue . A marked reduction in aberrant crypt number was observed in colonic tissue obtained from both the pectin-fed and butyrate-instilled groups relative to rats from the standard diet group . The average tumor volume per rat in both the pectin-fed and butyrate-instilled groups was significantly lower than in rats from the standard diet and the sodium butyrate vehicle-instilled groups . We conclude that high butyrate levels, either instilled or obtained following fermentation of soluble dietary fibers, inhibit early and late events in colon tumorigenesis by controlling the transcription expression and activity of key proteins involved in the apoptotic cascade. J Dairy Sci, 2000 Dec, 83(12), 2888 - 98 Effects of increasing levels of grain supplementation on rumen environment and lactation performance of dairy cows grazing grass-legume pasture; Reis RB et al.; The impact of supplemental energy on nutrient utilization, fiber digestion, rumen fermentation, and lactation performance was evaluated in dairy cows grazing pastures composed of brome, orchardgrass, red clover, and alfalfa . Three amounts {0, 5, and 10 kg dry matter (DM)/d} of ground dry shelled corn-based concentrate were supplemented to nine rumen cannulated Holstein cows in a 3 x 3 Latin square replicated three times . Cows were on average 84+/-13 d in milk and producing 41.6+/-5.9 kg of milk/d at the beginning of the study . An increase in amounts of concentrate in the diets was associated with an increase in milk production, solids-corrected milk, and concentrations of milk protein and SNF . Milk fat percentage and milk urea nitrogen concentration decreased linearly with supplementation . Milk production and protein percentage were 21.8, 26.8, and 30.4 kg/d, and 2.85, 2.95, and 3.05% for the increasing levels of concentrate, respectively . Intake and digestibility of DM and organic matter (OM) increased as grain supplementation increased . Ruminal pH and total volatile fatty acid concentration (VFA) were not affected by supplementation or the amount of concentrate . Ruminal ammonia concentration was reduced by supplementation, presumably due to a decrease in N intake and greater use of ammonia-N for rumen microbial protein synthesis . Rumen fermentation varied throughout the day, with lower mean pH and higher VFA concentrations at night . Supplementation increased total OM intake, decreased forage OM intake, and increased the proportion of OM that was digested in the intestines . Total DM intake by grazing dairy cows can be increased using ground dry shelled corn-based concentrate without causing negative effects on forage digestion. J Dairy Sci, 2000 Dec, 83(12), 2876 - 87 Partial replacement of forage with nonforage fiber sources in lactating cow diets . II . Digestion and rumen function; Pereira MN et al.; Replacement of forage with cereal byproducts may be a viable alternative for feeding dairy cows . The objective of this experiment was to evaluate total tract digestion and rumen fermentation profile when diets were formulated to contain low-forage neutral detergent fiber (NDF) (12.6% forage NDF, 18.8% total NDF), adequate NDF from forages (20% forage NDF, 24.4% total NDF) or low-forage NDF with high levels of NDF from cereal byproducts (12.7% forage NDF, 35.1% total NDF) . Sodium bicarbonate (0.8% of dry matter) was factorialized over these diets . Total tract apparent digestibilities of organic matter (OM) and carbohydrates were determined in 73 Holsteins . Eight rumen-cannulated cows were used concurrently to evaluate rumen fermentation profile and in situ degradation of forages . Bicarbonate did not increase NDF or OM digestibility, but increased intake of digestible OM . Rumen fermentation parameters were determined by dietary alfalfa NDF content . Adding alfalfa NDF to the low-forage, high-starch diet increased in situ degradation of forage NDF more than adding byproduct NDF . However, increased ruminal forage NDF degradability was not reflected in greater total tract NDF digestibility . Replacement of dietary starch with NDF from byproducts decreased OM digestibility, but energy intake was similar across diets due to increased intake. J Dairy Sci, 2000 Dec, 83(12), 2866 - 75 Performance of dairy cattle fed citrus pulp or corn products as sources of neutral detergent-soluble carbohydrates; Leiva E et al.; The effects of modifying the dietary profile of neutral detergent-soluble carbohydrates (NDSC) on milk production and rumen fermentation were determined . Corn silage and alfalfa hay-based diets were formulated to contain 40% calculated NDSC supplied primarily by dried citrus pulp as a source of neutral detergent-soluble fiber (NDSF), or corn products as sources of starch . Diets were compared within cow with reversal experiments with two periods . In experiment 1, 11 multiparous Holstein cows including three ruminally cannulated animals were individually fed diets containing 23.6% citrus pulp (diet CPD) or 25.3% corn hominy (diet HD) on a dry matter basis . In experiment 2, 184 animals fed as two groups received diets containing 20.5% citrus pulp (diet CPD) or 19.5% cornmeal (diet CMD) . Diets CPD provided more dietary NDSF and HD and CMD more starch . In experiment 1, cows fed HD had a greater milk protein percentage (+0.12%), and tended to yield more milk protein (0.08 kg/d) than cows fed CPD . Although ruminal H+ concentrations did not differ between diets, diet x time postfeeding interactions were significant . Ruminal organic acid concentrations did not differ between diets . In experiment 2, cows fed CMD yielded more milk (3.9 kg/d), 3.5% fat- and protein-corrected milk (2.6 kg/d), fat (0.05 kg/d), and protein (0.08 kg/d), whereas cows fed CPD produced greater concentrations of fat (+0.18%), and milk urea nitrogen (0.76 mg/dl) . Modifying the proportions of NDSC in the diet can alter milk production and composition, the pattern of ruminal fermentation, and N utilization in dairy cows. J Dairy Sci, 2000 Dec, 83(12), 2839 - 48 Effect of coarse or fine grinding on utilization of dry or ensiled corn by lactating dairy cows; San Emeterio F et al.; This study evaluated the effect of coarse or fine grinding of three forms of corn on the performance of lactating cows . Six diets, fed as total mixed rations, were identical except for the corn portion of the diet . Corn treatments were dry shelled corn, high moisture ensiled ear corn, and high moisture ensiled shelled corn, either coarsely or finely ground . The experimental design was a 6 x 6 Latin square with 36 cows . Eighteen cows were assigned to the six different treatments and were fed once daily . Within this group of 18 cows, six had a ruminal cannula and were used to evaluate nutrient digestibilities and ruminal fermentation . The remaining 18 cows, six of which were ruminally cannulated, were similarly assigned, except they were fed twice daily . In the group fed once daily, milk production and composition were not affected by treatment . Starch digestibility was greater with the high moisture and with the finely ground corn treatments . In addition, the high moisture ensiled corn treatments had reduced ruminal ammonia concentrations . In the group that was fed twice daily, milk production and protein yield were greatest for the finely ground high moisture ensiled shelled corn treatment . Starch utilization was improved by fine grinding . Lower ruminal ammonia concentrations were obtained with the high moisture ensiled corn treatments, and there was a tendency for reduced ammonia concentration with fine grinding . Results indicate that high moisture ensiled corn as well as fine grinding improved nitrogen and starch utilization. J Anim Sci, 2000 Dec, 78(12), 3155 - 68 Evaluation of models of acute and subacute acidosis on dry matter intake, ruminal fermentation, blood chemistry, and endocrine profiles of beef steers; Brown MS et al.; Crossbred steers (n = 20; 316 +/- 4 kg BW), each fitted with a ruminal cannula, were used to evaluate the effects of acute acidosis (AA) and subacute acidosis (SA) on DMI, ruminal fermentation, blood chemistry, and endocrine profiles . Animals were blocked by BW and assigned to treatments including 1) intraruminal (via cannula) steam-flaked corn (3% of BW; AA); 2) intraruminal dry-rolled wheat:dry-rolled corn (50:50; 1.5% of BW; SA); 3) offering forage-adapted steers ad libitum access to a 50% concentrate diet (AA control; AC); and 4) offering 50% concentrate diet-adapted steers ad libitum access to a 50% concentrate diet (SA control; SC) . Samples of ruminal fluid and whole blood were collected on the day of the challenge (d 0) and 3, 7, 10, and 14 d after the challenge . Daily DMI responded quadratically (P < 0.01) through d 7 for AA and SA steers and increased linearly (P < 0.01) for AC steers . Dry matter intake by AA steers reached a nadir (< 3 kg/d) on d 3 and gradually increased to a level similar to other treatments (7 kg/d) by d 10, whereas DMI by SA steers increased through d 3 . Blood pH, bicarbonate, base excess, and total CO2 were decreased (P < 0.03) for AA steers and increased (P < 0.03) for SC steers through d 7 . Ruminal pH decreased quadratically (P < 0.01) in AA and AC steers and increased (P = 0.01) in SA steers through d 7 . Ruminal total lactate concentration and osmolality responded quadratically (P < 0.01) for AA and AC steers . Ruminal total lactate peaked on d 3 for AA steers and on d 0 for AC and decreased to basal concentrations by d 7 . Plasma NEFA concentration increased (P < 0.04) on d 3 and 7 for AA steers . Serum Na decreased (P < 0.05) on d 0 for AA and SA steers and on d 7 and 14 for AA steers . Serum P decreased (P = 0.01) for AA steers through d 7 and decreased quadratically (P = 0.01) for AC steers through d 7 . Serum albumin and cholesterol decreased (P < 0.02) for AA and AC steers through d 7 . Area under the GH curve decreased (P = 0.02) for AA and AC steers through d 7 . Considerable variation was evident in the ability of an animal to cope with a carbohydrate challenge . Results of data modeling generally suggest that serum amylase activity, cholesterol and potassium concentrations, and plasma NEFA concentrations were useful in distinguishing between steers classified as experiencing subacute acidosis or not affected by a carbohydrate challenge. J Anim Sci, 2000 Dec, 78(12), 3144 - 54 Effects of supplementing prairie hay with corn and soybean meal on intake, digestion, and ruminal measurements by beef steers; Bodine TN et al.; Prairie hay supplemented with various amounts of corn and soybean meal was fed to steers in two experiments . Effects of supplementation on hay OM intake, digestion, and ruminal fermentation and kinetics were measured . A preliminary study was conducted to attain accurate values for OM intake and digestibility of prairie hay to be used in ration formulation using the NRC (1996) level 1 model . Ten steers (284 +/- 9 kg) given ad libitum access to chopped prairie hay (75% NDF, 6% CP) were supplemented with dry-rolled corn (0.75% of BW/d) plus soybean meal (0.25% of BW/d) . Hay OM intake was 1.85% of BW and hay OM digestibility was 48% . Based on results from the preliminary study, eight ruminally cannulated beef steers (317 +/- 25 kg) received a sequence of eight different supplementation combinations (2 x 4 factorial arrangement of treatments) . These supplements consisted of dry-rolled corn at either 0 or 0.75% of BW (DM basis) daily combined with one of four amounts of added soybean meal to provide between 0 and 1.3 g of degradable intake protein (DIP)/kg of BW . After supplements had been fed for 10 d, feces were collected for 4 d . Intake of hay and total OM increased quadratically (P < 0.01) in response to added DIP with or without supplemental corn . Hay OM digestibility increased quadratically (P = 0.03) as DIP was added when corn was fed in the supplement . Intake of digestible OM was greater (P < 0.01) with than without corn supplementation . Increasing DIP increased (P < 0.01) digestible OM intake regardless of whether corn was fed . Inadequate ruminally degraded protein in grain-based supplements decreased forage intake, digestibility, and energy intake of cattle fed low-quality prairie hay . Providing adequate supplemental DIP to meet total diet DIP needs seemed to overcome negative associative effects typically found from supplementing low-quality forages with large quantities of low-protein, high-starch feeds. Appl Microbiol Biotechnol, 2000 Nov, 54(5), 671 - 6 Recombinant expression analysis of natural and synthetic bovine alpha-casein in Escherichia coli; Goda SK et al.; As a prelude to developing a yeast-based fermentation process for the production of phenylalanine-free alpha-casein as a foodstuff for patients suffering from phenylketonuria, we cloned the gene encoding bovine alpha-casein . We synthesised a modified gene sequence encoding the same, but devoid of phenylalanine codons and with a codon bias similar to that of naturally occurring highly expressed genes in Saccharomyces cerevisiae . The results show that both gene sequences are readily expressed in Escherichia coli when cloned in an E . coli bacteriophage T7 promoter-driven plasmid vector . In this host, the natural and synthetic casein proteins were produced at levels equating to 18.0% and 7.6% of the cell's soluble protein, respectively. Appl Microbiol Biotechnol, 2000 Nov, 54(5), 647 - 51 Characterization of salt-tolerant mutant for enhancement of L-threonine production in Escherichia coli; Song KH et al.; Escherichia coli strain HS3, metabolically engineered to have Met(-), AHV(r), Ile(L) and AEC(r) characteristics, produced 58.0 g/l of L-threonine, but it was neither salt-tolerant nor osmotolerant; and the growth and threonine production of the strain were severely inhibited both by the addition of NaCl with a concentration higher than 2% and by the presence of glucose with a concentration higher than 10% . Therefore, salt-tolerant mutants were isolated . The salt-tolerant mutants, HS454 and HS528 which were derived from strain HS3, were both tolerant to salt (2%) and hyper-productive . The growth and L-threonine production by the mutant strain HS454 were almost unaffected by a glucose concentration lower than 10%, but gradually reduced with increasing glucose concentration, up to 15% . However, the mutant strain HS528 showed slightly enhanced growth and L-threonine production with increasing glucose concentration, up to 10-12.5% . Strains HS454 and HS528 produced 69.8 g/l and 74.0 g/l of L-threonine, respectively in a 5-1 jar fermentor. Biosci Biotechnol Biochem, 2000 Oct, 64(10), 2236 - 9 Effects of pH and light on the storage stability of the purple pigment, hordeumin, from uncooked barley bran fermented broth; Deguchi T et al.; The pigment retention rate of hordeumin was higher than that of two standard anthocyanidins, cyanidin and delphinidin, when hordeumin and anthocyanidins were dissolved in Walpole buffer (pH 1.0) and stored . Moreover, when pigment solutions were stored at 15 degrees C under light irradiation, the pigment retention rate of the hordeumin solution became higher than those of standard anthocyanidins (2 to 10 times) as the storage period increased . Comparing various pH buffers (MacIlvaine buffer, pH 2.2 to 7.0), the pigment retention rate of hordeumin at pH 5.0 was highest . Furthermore, the half-life of hordeumin at pH 5.0 was increased from 9 days to 17.5 days when nitrogen gas was bubbled into the hordeumin solution . We considered that the storage stability of hordeumin is higher than standard anthocyanidins because hordeumin is a complex with anthocyanin, tannin, and protein. J Rheumatol, 2000 Dec, 27(12), 2747 - 53 Mycoplasma fermentans in rheumatoid arthritis and other inflammatory arthritides; Horowitz S et al.; OBJECTIVE: To evaluate the association between infection with Mycoplasma fermentans (Mf) and rheumatoid arthritis (RA) and other inflammatory arthritides . METHODS: Screening of synovial fluid samples (SF) for Mf was done by culture and by polymerase chain reaction (PCR) in 38 and 34 RA patients, respectively, 8 undifferentiated arthritis (UDA), 9 reactive arthritis (ReA), and in 40 other arthritides . The prevalence of antibodies to Mf in these SF was determined by both ELISA and immunoblotting (IB) . Antibodies were measured also in sera of 88 RA patients, 28 ReA, 14 UDA, 71 other arthritides, and in 102 healthy blood donors . RESULTS: All SF were culture-negative for Mf, while 7 SF were positive by PCR (6/34 RA and 1/8 UDA) . SF from patients with other arthritides and ReA were PCR-negative . The prevalence of anti-Mf antibodies in SF of RA patients was significantly higher than in SF of other arthritides (p = 0.01) . In 47% (17/38) of all RA (including the 6 PCR-positive patients), the level of antibodies to Mf in their SF was higher than that in sera, compared to 7.5% (3/40) in other arthritides (p = 0.0002) . There was no significant difference in the prevalence of serum antibodies to Mf between patients with RA, other arthritides, and healthy controls . By IB with Mf sonicate, binding to Mf peptides P107, P48, and P29 was detected in SF of 7/11 RA patients but not in 11 patients with traumatic arthritis . Specific binding to Mf membrane lipoproteins was also more prevalent in SF of RA patients than in other arthritides (p = 0.038) . CONCLUSION: The finding that both Mf DNA and specific antibodies to Mf were present in the SF of RA patients suggests that in some RA patients Mf may play a role in initiating or perpetuating synovitis. J AOAC Int, 2000 Nov-Dec, 83(6), 1401 - 9 Deuterium nuclear magnetic resonance spectroscopy and stable carbon isotope ratio analysis/mass spectrometry of certain monofloral honeys; Giraudon S et al.; Quantitative deuterium nuclear magnetic resonance spectroscopy (NMR) has been used in conjunction with stable carbon isotope ratio analysis/mass spectrometry to refine the detection of sugars that have been added to monofloral honeys . The 13C content of sugars indicates the type of photosynthetic metabolism of the plant that synthesized them; the deuterium content is more characteristic of secondary metabolism and of environmental factors . Consequently, determination of the 13C content of honeys and of proteins extracted from the honeys can be used to detect the addition of C4 plant sugars (cane or corn), but it does not reveal the addition of C3 plant sugars such as beet sugar . Deuterium NMR gives useful information for some monofloral honeys . NMR measurement is performed on ethanol obtained from fermentation of the honey and extracted by distillation . The isotopic composition of the ethanol indicates the nature of the sugars from which it was derived . Various types of monofloral honeys were studied, and the results obtained with commercially available honeys demonstrate the usefulness of isotopic analysis and the need to compile a database of authentic honeys to validate or affirm certain results. Curr Genet, 2000 Nov, 38(4), 202 - 7 Functional co-operation between the nuclei of Saccharomyces cerevisiae and mitochondria from other yeast species; Spirek M et al.; We elaborated a simple method that allows the transfer of mitochondria from collection yeasts to Saccharomyces cerevisiae . Protoplasts prepared from different yeasts were fused to the protoplasts of the ade2-1, ura3-52, kar1-1, rho0 strain of S . cerevisiae and were selected for respiring cybrids on plates containing 5-fluoroorotic acid and a non-fermentable carbon source . The identity of putative cybrids was assessed by restriction analysis of mitochondrial DNA, pulse field electrophoresis and tetrad analysis . In the comprehensive screening, only mitochondrial genomes from synonymous species (S . italicus, S . oviformis, S . capensis and S . chevalieri) exhibited complete compatibility with S . cerevisiae nuclei . The closely related S . douglasii mitochondrial genome could also partially restore respiration-deficiency in rho0 S . cerevisiae, whereas mitochondrial genomes from phylogenetically less related species could not. J Appl Microbiol, 2000 Dec, 89(6), 935 - 43 Modelling inactivation of Escherichia coli by low pH: application to passage through the stomach of young and elderly people; Takumi K et al.; AIM: To estimate the survival of enteropathogenic Escherichia coli after passage through the stomach of young and elderly people . METHODS AND RESULTS: Using enterohaemorrhagic E . coli O157 and a non-pathogenic laboratory strain, inactivation in a pH range between 1.5 and 4.0 was experimentally quantified . Gastric pH and transport have previously been studied in human volunteers following consumption of a solid meal . Combining all these findings, time series of surviving bacteria were mathematically predicted and subsequently, the predictions were validated with in vitro experiments using a pH-controlled fermentor . On average, 20-80% of ingested E . coli are estimated to arrive in the small intestine without inactivation by low pH . The mean overall gastric passage was similar for young and elderly subjects . CONCLUSIONS: The tested E . coli strains can survive the human stomach with a high probability . SIGNIFICANCE AND IMPACT OF THE STUDY: Survival of E . coli under conditions of changing pH in the stomach may be predicted by batch experiments at constant pH . The effectiveness of the gastric acid barrier strongly depends on buffering effects of food. J Appl Microbiol, 2000 Nov, 89(5), 876 - 83 Use of a PGU1 recombinant Saccharomyces cerevisiae strain in oenological fermentations; Vilanova M et al.; AIM: The aim of this work was the construction of an oenological Saccharomyces cerevisiae strain able to overexpress the PGU1 gene in order to be used in trial fermentations . METHODS AND RESULTS: The recombinant strain is able to secrete an active endopolygalacturonase into the medium leaving its fermentation ability essentially unchanged . Wines obtained with the recombinant strain and the untransformed counterpart did not differ in their physicochemical parameters or major sensory characteristics . The time needed for wine filtration was dramatically reduced in wines elaborated with the PGU1 recombinant strain, and was comparable to the filtration time shown by wines elaborated from must supplemented with fungal pectolytic enzymes . CONCLUSIONS: The oenological strain constructed in this work secretes an endopolygalacturonase into the wine in an efficient manner, resulting in an improvement in wine filtration but preserving wine typicality and keeping the methanol levels unchanged . SIGNIFICANCE AND IMPACT OF THE STUDY: The PGU1 recombinant strains could be used in oenological fermentations as an alternative to commercial pectolytic enzymes of fungal origin. J Appl Microbiol, 2000 Nov, 89(5), 834 - 9 Changes in major components of tea fungus metabolites during prolonged fermentation; Chen C et al.; Changes in major components and microbes in tea fungus broth (or kombucha; teakwass) prepared from nine different sources during a prolonged fermentation of up to 60 days were investigated . Cell concentrations of both yeasts and acetic acid bacteria in broth were generally higher than those in the cellulosic pellicles . The residual sucrose concentration decreased linearly with time, although the rate fell after the first month . Metabolic fates of glucose and fructose produced as a result of the hydrolysis of sucrose were different . Glucose was not produced in parallel with fructose (0.085 g 100 ml(-1) d(-1)) but was produced with a lower initial rate (0.041 g 100 ml(-1) d(-1)) . Both titratable acidity and gluconic acid increased steadily with time for all samples, although gluconic acid was not generated for 6 days until the fermentation had begun . Acetic acid increased slowly to a maximum value of 1.1 g 100 ml(-1) after 30 days; thereafter, it decreased gradually . Gluconic acid contributed to the titratable acidity and thus, the taste of tea fungus broth, during the final stage of fermentation . It is concluded that the desired quality or composition of kombucha can be obtained through the proper control of fermentation time. Enzyme Microb Technol, 2001 Jan 2, 28(1), 16 - 24 Expression of E . coli araBAD operon encoding enzymes for metabolizing L-arabinose in Saccharomyces cerevisiae; Sedlak M et al.; The Escherichia coli araBAD operon consists of three genes encoding three enzymes that convert L-arabinose to D-xylulose-5 phosphate . In this paper we report that the genes of the E . coli araBAD operon have been expressed in Saccharomyces cerevisiae using strong promoters from genes encoding S . cerevisiae glycolytic enzymes (pyruvate kinase, phosphoglucose isomerase, and phosphoglycerol kinase) . The expression of these cloned genes in yeast was demonstrated by the presence of the active enzymes encoded by these cloned genes and by the presence of the corresponding mRNAs in the new host . The level of expression of L-ribulokinase (araB) and L-ribulose-5-phosphate 4-epimerase (araD) in S . cerevisiae was relatively high, with greater than 70% of the activity of the enzymes in wild type E . coli . On the other hand, the expression of L-arabinose isomerase (araA) reached only 10% of the activity of the same enzyme in wild type E . coli . Nevertheless, S . cerevisiae, bearing the cloned L-arabinose isomerase gene, converted L-arabinose to detectable levels of L-ribulose during fermentation . However, S . cerevisiae bearing all three genes (araA, araB, and araD) was not able to produce detectable amount of ethanol from L-arabinose . We speculate that factors such as pH, temperature, and competitive inhibition could reduce the activity of these enzymes to a lower level during fermentation compared to their activity measured in vitro . Thus, the ethanol produced from L-arabinose by recombinant yeast containing the expressed BAD genes is most likely totally consumed by the cell to maintain viability. Enzyme Microb Technol, 2000 Dec, 27(10), 774 - 777 Production of poly(3-hydroxybutyrate) from inexpensive substrates; Kim BS; Two inexpensive substrates, starch and whey were used to produce poly(3-hydroxybutyrate) (PHB) in fed-batch cultures of Azotobacter chroococcum and recombinant Escherichia coli, respectively . Oxygen limitation increased PHB contents in both fermentations . In fed-batch culture of A . chroococcum, cell concentration of 54 g l(-1) with 46% PHB was obtained with oxygen limitation, whereas 71 g l(-1) of cell with 20% PHB was obtained without oxygen limitation . The timing of PHB biosynthesis in recombinant E . coli was controlled using the agitation speed of a stirred tank fermentor . A PHB content of 80% could be obtained with oxygen limitation by increasing the agitation speed up to only 500 rpm. Cancer Res, 2000 Dec 1, 60(23), 6663 - 9 A tetravalent single-chain antibody-streptavidin fusion protein for pretargeted lymphoma therapy; Schultz J et al.; Single-chain Fv antibody fragments from the CD20-specific murine monoclonal antibody B9E9 were genetically engineered as streptavidin fusions {single-chain Fv-streptavidin (scFvSA) fusion protein} for use in pretargeted radioimmunotherapy . The scFvSA constructs were expressed as soluble, tetrameric species in the periplasm of Escherichia coli . Expression levels were affected by the order of the variable regions and the length and composition of the single-chain Fv linker . The best expressor was obtained with the variable regions in the heavy chain-light chain configuration separated by a 25-mer Gly4Ser linker . This construct produced 250-300 mg of soluble, tetrameric fusion protein per liter of fermentor culture . The fusion protein (Mr 173,600) was purified from crude lysates by iminobiotin affinity chromatography with an overall yield of about 50% and was analyzed for functionality both in vitro and in vivo . Immunoreactivity of the scFvSA fusion protein and its nanomolar affinity to CD20-positive Ramos cells were comparable with the B9E9 monoclonal antibody . The fusion protein had a biotin dissociation rate identical to recombinant streptavidin and bound an average of 3.6 biotins/molecule of a possible 4 biotins/molecule . Labeled fusion protein cleared from the blood of BALB/c mice with a P half-life of about 16 h . In nude mice bearing Ramos xenografts, the fusion protein demonstrated sufficient tumor localization of functional streptavidin to enable efficient, tumor-specific targeting of a subsequently administered radionuclide-chelate/biotin molecule . These results suggest that large quantities of functional scFvSA can be produced for clinical testing as a therapy for non-Hodgkin's lymphoma. Prikl Biokhim Mikrobiol, 2000 Nov-Dec, 36(6), 647 - 51 {Effect of space flight conditions on properties of hydrocarbon-oxidizing bacteria}; Ermolenko ZM et al.; Results of experiments on the Mir space station (EO-25 and EO-26) demonstrated that the conditions of orbital flight, primarily the cosmic radiation, was a mutagenic factor affecting both the genotype and phenotype of an oil-oxidizing bacterial strain, Mycobacterium flavescens EX-91 . The emerging mutants differed from original culture by the rate of colony growth and the ability to ferment certain carbohydrates or synthesize beta-galactosidase . Changes in the rate of utilization of raw oil and individual hydrocarbon types (constituting model mixtures) suggest that cosmic radiation may serve as a means of obtaining mutant clones of microorganisms with new properties. Gut, 2001 Jan, 48(1), 53 - 61 Only fibres promoting a stable butyrate producing colonic ecosystem decrease the rate of aberrant crypt foci in rats; Perrin P et al.; BACKGROUND: Dietary fibres have been proposed as protective agents against colon cancer but results of both epidemiological and experimental studies are inconclusive . AIMS: Hypothesising that protection against colon cancer may be restricted to butyrate producing fibres, we investigated the factors needed for long term stable butyrate production and its relation to susceptibility to colon cancer . METHODS: A two part randomised blinded study in rats, mimicking a prospective study in humans, was performed using a low fibre control diet (CD) and three high fibre diets: starch free wheat bran (WB), type III resistant starch (RS), and short chain fructo-oligosaccharides (FOS) . Using a randomised block design, 96 inbred rats were fed for two, 16, 30, or 44 days to determine the period of adaptation to the diets, fermentation profiles, and effects on the colon, including mucosal proliferation on day 44 . Subsequently, 36 rats fed the same diets for 44 days were injected with azoxymethane and checked for aberrant crypt foci 30 days later . RESULTS: After fermentation had stabilised (44 days), only RS and FOS produced large amounts of butyrate, with a trophic effect in the large intestine . No difference in mucosal proliferation between the diets was noted at this time . In the subsequent experiment one month later, fewer aberrant crypt foci were present in rats fed high butyrate producing diets (RS, p=0.022; FOS, p=0.043) . CONCLUSION: A stable butyrate producing colonic ecosystem related to selected fibres appears to be less conducive to colon carcinogenesis. Biochim Biophys Acta, 2001 Jan 19, 1503(3), 329 - 40 The calorimetric-respirometric ratio is an on-line marker of enthalpy efficiency of yeast cells growing on a non-fermentable carbon source; Dejean L et al.; Although on-line calorimetry has been widely used to detect transitions in global metabolic activity during the growth of microorganisms, the relationships between oxygen consumption flux and heat production are poorly documented . In this work, we developed a respirometric and calorimetric approach to determine the enthalpy efficiency of respiration-linked energy transformation of isolated yeast mitochondria and yeast cells under growing and resting conditions . On isolated mitochondria, the analysis of different phosphorylating and non-phosphorylating steady states clearly showed that the simultaneous measurements of heat production and oxygen consumption rates can lead to the determination of both the enthalpy efficiency and the ATP/O yield of oxidative phosphorylation . However, these determinations were made possible only when the net enthalpy change associated with the phosphorylating system was different from zero . On whole yeast cells, it is shown that the simultaneous steady state measurements of the heat production and oxygen consumption rates allow the enthalpy growth efficiency (i.e . the amount of energy conserved as biomass compared to the energy utilised for complete catabolism plus anabolism) to be assessed . This method is based on the comparison between the calorimetric-respirometric ratio (CR ratio) determined under growth versus resting conditions during a purely aerobic metabolism . Therefore, in contrast to the enthalpy balance approach, this method does not rely on the exhaustive and tedious determinations of the metabolites and elemental composition of biomass . Thus, experiments can be performed in the presence of non-limiting amounts of carbon substrate, an approach which has been successfully applied to slow growing cells such as yeast cells expressing wild-type or a mutant rat uncoupling protein-1. Mol Microbiol, 2000 Nov, 38(4), 904 - 15 Proton motive force drives the interaction of the inner membrane TolA and outer membrane pal proteins in Escherichia coli; Cascales E et al.; The Tol-Pal system of the Escherichia coli envelope is formed from the inner membrane TolQ, TolR and TolA proteins, the periplasmic TolB protein and the outer membrane Pal lipoprotein . Any defect in the Tol-Pal proteins or in the major lipoprotein (Lpp) results in the loss of outer membrane integrity giving hypersensitivity to drugs and detergents, periplasmic leakage and outer membrane vesicle formation . We found that multicopy plasmid overproduction of TolA was able to complement the membrane defects of an lpp strain but not those of a pal strain . This result indicated that overproduced TolA has an envelope-stabilizing effect when Pal is present . We demonstrate that Pal and TolA formed a complex using in vivo cross-linking and immunoprecipitation experiments . These results, together with in vitro experiments with purified Pal and TolA derivatives, allowed us to show that Pal interacts with the TolA C-terminal domain . We also demonstrate using protonophore, K+ carrier valinomycin, nigericin, arsenate and fermentative conditions that the proton motive force was coupled to this interaction. J Exp Bot, 2000 Nov, 51(352), 1939 - 44 Abscisic acid and hypoxic induction of anoxia tolerance in roots of lettuce seedlings; Kato-Noguchi H; Lettuce (Lactuca sativa L.) seedlings were subjected to anoxic stress after ABA-pretreatment (ABA-PT) or hypoxic-pretreatment (H-PT) . The H-PT increased the survivability of the anoxia in roots of the seedlings by 5.2-fold compared to that of non-pretreated (N-PT) seedlings . ABA-PT also increased the survivability at concentrations greater than 1 microM, and the survivability increased with increasing ABA doses . At 100 microM ABA, the survivability was 4.5-fold greater than that of N-PT seedlings . During pretreatment periods, alcohol dehydrogenase (ADH, EC 1.1.1.1) activity in the roots became 3.1- and 3.4-fold greater than that of N-PT seedlings following 100 microM ABA-PT and H-PT seedlings, respectively . After the onset of anoxic stress, ADH activities in all roots increased, but the activities in H-PT and ABA-PT roots remained much greater than that in N-PT roots, and the average ethanol production rate for the initial 6 h was 5.3, 4.0 and 1.4 micromol g(-1) FW h(-1) for H-PT, ABA-PT and N-PT roots, respectively . Roots of the seedlings lost ATP rapidly under anoxic stress; however, the decrease in ATP was much slower in the ABA-PT and H-PT seedlings than in the N-PT seedlings . These results suggest that the ABA-PT and H-PT may maintain ATP levels due to activation of ethanolic fermentation, which may be one of the causes of the increasing anoxia tolerance in the seedling roots . Measurement of endogenous ABA levels, however, showed that ABA levels did not increase during the H-PT, suggesting that the H-PT does not increase tolerance through an increase in ABA levels. FEMS Microbiol Lett, 2000 Dec 15, 193(2), 269 - 73 Dynamic accumulation and degradation of poly(3-hydroxyalkanoate)s in living cells of Azotobacter vinelandii UWD characterized by (13)C NMR; Yan YB et al.; The synthesis and degradation of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-hydroxyvalerate) (P(HB-co-HV)) by Azotobacter vinelandii UWD were investigated using natural abundance solution (13)C nuclear magnetic resonance (NMR) in vivo in shake flask culture and in fermenter culture . The synthesis and the degradation of poly(3-hydroxyalkanoate)s (PHA) monomers hydroxybutyrate (HB) and hydroxyvalerate (HV) had different rates . The amount of HB and HV increased dramatically in the initial degradation stage . The results suggest that the intracellular PHA of strain UWD was the subject of dynamic metabolic processing . (13)C NMR in vivo analysis provided a rapid, easy, accurate, non-destructive method to obtain valuable information on the metabolism of PHA. Int Microbiol, 1998 Jun, 1(2), 143 - 8 The role of non-Saccharomyces yeasts in industrial winemaking; Esteve-Zarzoso B et al.; The fermentation of grape juice into wine is a complex microbiological process, in which yeasts play a central role . Traditionally, identification and characterization of yeast species have been based on morphological and physiological characteristics . However, the application of molecular biology techniques represents an alternative to the traditional methods of yeast identification and are becoming an important tool in solving industrial problems . Although Saccharomyces cerevisiae is responsible for the alcoholic fermentation, the presence of non-Saccharomyces species could be important since they produce secondary metabolites, which can contribute to the final taste and flavor of wines. Eur J Biochem, 2000 Dec, 267(24), 7082 - 93 The iron-sulfur clusters in 2-hydroxyglutaryl-CoA dehydratase from Acidaminococcus fermentans . Biochemical and spectroscopic investigations; Hans M et al.; The reversible dehydration of (R)-2-hydroxyglutaryl-CoA to (E)-glutaconyl-CoA is catalysed by the combined action of two oxygen-sensitive enzymes from Acidaminococcus fermentans, the homodimeric component A (2 x 27 kDa) and the heterodimeric component D (45 and 50 kDa) . Component A was purified to homogeneity (specific activity 25-30 s-1) using streptavidin-tag affinity chromatography . In the presence of 5 mM MgCl2 and 1 mM ADP or ATP, component A could be stabilized and stored for 4-5 days at 4 degrees C without loss of activity . The purification of component D from A . fermentans was also improved as indicated by the 1.5-fold higher specific activity (15 s-1) . The content of 1.0 riboflavin 5'-phosphate (FMN) per heterodimer could be confirmed, whereas in contrast to an earlier report only trace amounts of riboflavin (< 0.1) could be detected . Each active component contains an oxygen sensitive diamagnetic {4Fe-4S}2+ cluster as revealed by UV-visible, EPR and Mossbauer spectroscopy . Reduction of the {4Fe-4S}2+ cluster in component A with dithionite yields a paramagnetic {4Fe-4S}1+ cluster with the unusual electron spin ground state S = 3/2 as indicated by strong absorption type EPR signals at high g values, g = 4-6 . Spin-Hamiltonian simulations of the EPR spectra and of magnetic Mossbauer spectra were performed to determine the zero field splitting (ZFS) parameters of the cluster and the 57Fe hyperfine interaction parameters . The electronic properties of the {4Fe-4S}2+, 1+ clusters of component A are similar to those of the nitrogenase iron protein in which a {4Fe-4S}2+ cluster bridges the two subunits of the homodimeric protein . Under air component A looses its activity within seconds due to irreversible degradation of its {4Fe-4S}2+ cluster to a {2Fe-2S}2+ cluster . The {4Fe-4S}2+ cluster of component D could not be reduced to a {4Fe-4S}1+ cluster, even with excess of Ti(III)citrate or dithionite . Exposure to oxic conditions slowly converts the diamagnetic {4Fe-4S}2+ cluster of component D to a paramagnetic {3Fe-4S}+ cluster concomitant with loss of activity (30% within 24 h at 4 degrees C). Bioseparation, 2000, 9(3), 163 - 6 Separation of lactic acid from fermented broth by reactive extraction; Jarvinen M et al.; The separation of lactic acid from complex fermentation broth was examined . Liquid-liquid extraction using reversible chemical complexation for reactive extraction was chosen to be the separation method . Over 50% yield of lactic acid was obtained from fermented broth in a single extraction step, when using the tertiary amine as the extractant, 1-dekanol as the diluent and trimethylamine (TMA) as the stripping solution . The effect of complex media on the extraction behaviour has hardly been examined previously. J Dairy Sci, 2000 Nov, 83(11), 2609 - 19 Milk composition and apparent digestibilities of dietary fatty acids in lactating dairy cows abomasally infused with Cis or Trans fatty acids; Romo GA et al.; Fat supplementation of diets for dairy cows produces changes in nutrient supply and milk composition . The effect of abomasal infusion of either cis-C18:1 or trans-C18:1 fatty acid isomers on the digestibility of fatty acids and milk composition was determined in lactating dairy cows . Six multiparous midlactation Holstein cows were used and fed a control diet containing 50% forage and 50% concentrate . Treatments were (per day): no infusion, infusion of a 630-g fat mixture high in cis-C18:1 isomers, and infusion of a 623-g fat mixture high in trans-C18:1 isomers using two 3 x 3 Latin squares with 4-wk experimental periods . Fat infusion did not affect total dry matter intake and increased apparent digestibilities of total fatty acids . Apparent digestibilities of C18 fatty acids were directly related to the number of double bonds within isomers, and cis-C18:1 isomers were slightly more digestible than trans-C18:1 isomers . The lower yield of C12:0, C14:0, and C16:0 fatty acids in milk fat and higher milk citrate observed when cows were infused with trans-C18:1 suggests a depressed de novo milk fatty acid synthesis . Effects of trans infusion on milk fat were independent of ruminal fermentation, fatty acid apparent absorption, and fatty acid plasma concentrations . Lower milk protein yield in cows infused with fat may have been caused by a decrease in milk protein synthesis. J Dairy Sci, 2000 Nov, 83(11), 2574 - 9 Effect of sugars and malate on ruminal microorganisms; Martin SA et al.; The objective of this study was to examine the effects of a commercial feed supplement that contains sugars and malate on lactate fermentation by Selenomonas ruminantium grown in batch culture . Experiments also were conducted to examine the effects of this feed supplement on the mixed ruminal microorganism fermentation of ground corn and soluble starch in the presence and absence of 5 mg/kg of monensin . When S . ruminantium strains HD4 and H18 were incubated in basal medium that contained DL-lactate, some DL-lactate was utilized by both strains after 24 h . In the presence of 1 g/L of sugars plus malate commercial feed supplement, both strains used most of the carbohydrate associated with the feed supplement between 6 and 8 h, and lactate was the main end product . In ground corn fermentations by mixed ruminal microorganisms, 2.25 and 3.25 g/L of sugars plus malate commercial feed supplement increased concentrations of acetate, propionate, and total volatile fatty acids, while 3.25 g/L increased lactate and decreased final pH and butyrate . Fermentation of soluble starch in the presence of both concentrations of sugars plus malate commercial feed supplement increased concentrations of acetate, propionate, and total volatile fatty acids and decreased the acetate:propionate ratio . In the presence of 5 mg/kg of monensin, sugars plus malate treatment increased concentrations of propionate and total volatile fatty acids in ground corn and soluble starch fermentations . Collectively, these results suggest that the sugars plus malate commercial feed supplement stimulates the ruminal fermentation. Br J Nutr, 2000 Oct, 84(4), 565 - 74 Properties of maltodextrins and glucose syrups in experiments in vitro and in the diets of laboratory animals, relating to dental health; Grenby TH et al.; The objective of the study was to examine the cariogenic potentials of maltodextrins and glucose syrups (two glucose polymers derived from starch) using a range of techniques in vitro and in laboratory animals . The experimental methods used were: (1) measurement of acid production from glucose syrups and maltodextrins by human dental plaque micro-organisms; (2) evaluation of the role salivary alpha-amylase in degrading oligosaccharides (degree of polymerisation > 3) in the glucose polymers, estimating the products by HPLC; (3) assessment of the fermentability of trioses relative to maltose; (4) measurement of dental caries levels in three large-scale studies in laboratory rats fed on diets containing the glucose polymers . It was found that acid production from the glucose polymers increased as their higher saccharide content fell . Salivary alpha-amylase rapidly degraded the oligosaccharides (degree of polymerisation > 3), mainly to maltose and maltotriose . In the presence of oral micro-organisms, maltotriose took longer to ferment than maltose, but by the end of a 2 h period the total amount of acid produced was the same from both . Incorporated into the diets in solid form, the glucose syrups and maltodextrins were associated with unexpectedly high levels of dental caries . In conclusion, the findings were unforeseen in the light of earlier data that a glucose syrup was less cariogenic than sucrose. Br J Nutr, 2000 Oct, 84(4), 429 - 37 Intestinal metabolism of rye lignans in pigs; Glitso LV et al.; To study the intestinal metabolism of lignans, the concentrations of plant and mammalian lignans in intestinal digesta sampled along the intestinal tract of pigs were determined by isotope dilution GC-MS . The pigs were fed rye-bread diets made from either whole rye-grains or rye-grain milling fractions enriched in pericarp-testa, aleurone or endosperm cells . The content and characteristics of dietary fibre varied between diets and had been shown to induce different colon fermentation patterns . As the metabolism of lignans depends on the action of the intestinal flora, we tested whether the rye-bread diets influence the metabolism of lignans . In the ileum, the lignans were mainly present as conjugated plant lignans, which were determined only when the analytical procedure included a hydrolysis step . High recovery of dietary lignans in the ileum may indicate that the lignans enter the enterohepatic circulation . In addition, two to three times the intake of lignans were recovered in the faeces when the diets had a high content of dietary fibre suggesting underestimation of plant lignans in the diet . Most of the plant lignans disappeared from the intestinal tract between the terminal ileum and the caecum . The intestinal concentrations and the disappearance of lignans correlated with the content of lignans in the diet, being highest on the pericarp-testa diet and lowest on the endosperm diet . No effect of fermentation pattern on the intestinal metabolism of lignans was observed . The lignans were liberated from the pericarp-testa diet although the plant cell walls remained largely undegraded. Curr Opin Biotechnol, 2000 Dec, 11(6), 572 - 8 Online NMR for monitoring biocatalysed reactions; Weber H et al.; Monitoring biocatalysed reactions and metabolic pathways using NMR spectroscopy is of growing interest . As a non-invasive analytical method providing simultaneous information about intracellular and extracellular constituents, it is superior to other analytical techniques and has a wide range of applications: kinetics and stoichiometrics of metabolic events, metabolic fluxes and enzyme activities can be detected in situ or after taking a sample from the biotransformation mixture . New NMR pulse sequences provide even more valuable experiments in these fields . Research topics range from the monitoring of polymer formation to fermentations producing beverages or antibiotics . Routine monitoring of industrial fermentations by NMR seems to be imminent. Nat Biotechnol, 2000 Dec, 18(12), 1283 - 6 Increasing galactose consumption by Saccharomyces cerevisiae through metabolic engineering of the GAL gene regulatory network; Ostergaard S et al.; Increasing the flux through central carbon metabolism is difficult because of rigidity in regulatory structures, at both the genetic and the enzymatic levels . Here we describe metabolic engineering of a regulatory network to obtain a balanced increase in the activity of all the enzymes in the pathway, and ultimately, increasing metabolic flux through the pathway of interest . By manipulating the GAL gene regulatory network of Saccharomyces cerevisiae, which is a tightly regulated system, we produced prototroph mutant strains, which increased the flux through the galactose utilization pathway by eliminating three known negative regulators of the GAL system: Gal6, Gal80, and Mig1 . This led to a 41% increase in flux through the galactose utilization pathway compared with the wild-type strain . This is of significant interest within the field of biotechnology since galactose is present in many industrial media . The improved galactose consumption of the gal mutants did not favor biomass formation, but rather caused excessive respiro-fermentative metabolism, with the ethanol production rate increasing linearly with glycolytic flux. Biotechnol Prog, 2000 Nov-Dec, 16(6), 993 - 9 Production of cyclodepsipeptides destruxin A and B from Metarhizium anisopliae; Liu BL et al.; Maltose and peptone were the best carbon and nitrogen sources for the production of destruxins from Metarhizium anisopliae . With the addition of 0.1% (w/v) beta-alanine to the basal medium, the yields of cyclodepsipeptides DA and DB were 7.2 and 279 mg/L, respectively, which was 2-fold higher than that of control experiment . Response surface methodology (RSM) was applied to optimize the compositions of maltose, peptone, beta-alanine, and glucose used in a shaker-flask cultivation of M . anisopliae for the production of DA and DB . Estimated optimal compositions for the DA production were maltose 2.58%, peptone 0.72%, beta-alanine 0.02%, and glucose 0.55% . The predicted DA yield was 18.5 mg/L . On the other hand, the optimal compositions for DB production were maltose 2.51%, peptone 0.75%, beta-alanine 0.02%, and glucose 0.43% . A maximum DB yield of 232 mg/L was predicted . These were confirmed by cultivation experiments conducted at the optimized conditions for maximum destruxins production in a shaker-flask . Furthermore, a modest high level of DA (49 mg/L) and DB (268 mg/L) yields were obtained by employing the response surface methodology optimized DB production medium in a no-baffle, stirred-tank fermentor. Biotechnol Prog, 2000 Nov-Dec, 16(6), 958 - 65 Improved performances and control of beer fermentation using encapsulated alpha-acetolactate decarboxylase and modeling; Dulieu C et al.; The use of the enzyme alpha-acetolactate decarboxylase allows the acceleration of beer fermentation/maturation because it shunts diacetyl formation, whose elimination is the rate-limiting step of the process . To obtain a cost reduction by using this exogenous enzyme, we propose a new process involving recoverable encapsulated alpha-acetolactate decarboxylase . The performance of traditional and new processes was investigated by a modeling approach . A simple model, focused on alpha-acetolactate and diacetyl profiles during beer fermentation, was set up . The simulated profiles are consistent with literature data . This study shows also that encapsulated alpha-acetolactate decarboxylase allows the acceleration of beer fermentation as efficiently as free alpha-acetolactate decarboxylase . The advantage of immobilized alpha-acetolactate decarboxylase versus free enzyme is that it is recoverable and reusable, which means a process cost reduction. Biotechnol Prog, 2000 Nov-Dec, 16(6), 940 - 6 Enhanced production of (R)-1,2-propanediol by metabolically engineered Escherichia coli; Altaras NE et al.; 1,2-Propanediol (1,2-PD) is a major commodity chemical currently derived from propylene . Previously, we have demonstrated the production of enantiomerically pure (R)-1,2-propanediol from glucose by an engineered E . coli expressing genes for NADH-linked glycerol dehydrogenase and methylglyoxal synthase . In this work, we investigate three methods to improve 1,2-PD in E . coli . First, we investigated improving the host by eliminating production of a byproduct, lactate . To do this, we constructed strains with mutations in two enzymes involved in lactate production, lactate dehydrogenase and glyoxalase I . (Surprisingly, when mutations were made in its ability to produce lactate, one strain of E . coli {MM294}, produced a small amount of 1,2-PD without any added genes.) Second, we constructed a complete pathway to 1,2-PD from the glycolytic intermediate, dihydroxyacetone phosphate . Our previous 1, 2-PD producing strains relied on at least one endogenous E . coli activity and only produced 0.7 g/L of 1,2-PD . The complete pathway involved the coexpression of methylglyoxal synthase (mgs), glycerol dehydrogenase (gldA), and either yeast alcohol dehydrogenase (adhI) or E . coli 1,2-propanediol oxidoreductase (fucO) . Third, we investigated bioprocessing improvements by carrying out a fed-batch fermentation with the best engineered strain (expressing mgs, gldA, and fucO) . A final titer of 4.5 g/L of (R)-1,2-PD was produced, with a final yield of 0.19 g of 1,2-PD per gram of glucose consumed . This work provides a basis for further strain and process improvement. J Antibiot (Tokyo), 2000 Sep, 53(9), 895 - 902 4'-N-methyl-5'-hydroxystaurosporine and 5'-hydroxystaurosporine, new indolocarbazole alkaloids from a marine Micromonospora sp . strain; Hernandez LM et al.; Two new indolocarbazole alkaloids, 4'-N-methyl-5'-hydroxystaurosporine (2) and 5'-hydroxystaurosporine (3), were isolated together with the known staurosporine (1) from the culture broth of a marine Micromonospora sp . (strain L-31-CLCO-002) . The fermentation, structural data and cytotoxic activities of these compounds against various tumor cell lines are given. J Antibiot (Tokyo), 2000 Sep, 53(9), 863 - 72 Novel human topoisomerase I inhibitors, topopyrones A, B, C and D . I . Producing strain, fermentation, isolation, physico-chemical properties and biological activity; Kanai Y et al.; In the course of a screening program for specific inhibitors of human topoisomerase I using a recombinant yeast, we have discovered four new active compounds . All four compounds were isolated from the culture broth of a fungus, Phoma sp . BAUA2861, and two of them were isolated from the culture broth of a fungus, Penicillium sp . BAUA4206 . We designated these compounds as topopyrones A, B, C and D . Topopyrones A, B, C and D selectively inhibited recombinant yeast growth dependent on expression of human topoisomerase I with IC50 values of 1.22, 0.15, 4.88 and 19.63 ng/ml, respectively . The activity and selectivity of topopyrone B were comparable to those of camptothecin . The relaxation of supercoiled pBR322 DNA by human DNA topoisomerase I was inhibited by these compounds, however they did not inhibit human DNA topoisomerase II . Topopyrones A, B, C and D were cytotoxic to all tumor cell lines when tested in vitro . Topopyrone B has potent inhibitory activity against herpesvirus, especially varicella zoster virus (VZV) . It inhibited VZV growth with EC50 value of 0.038 microg/ml, which is 24-fold stronger than that of acyclovir (0.9 microg/ml) . Topopyrones A, B, and C were inhibitory to Gram-positive bacteria. Z Naturforsch {C}, 2000 Sep-Oct, 55(9-10), 713 - 7 Biotransformation of two cytotoxic terpenes, alpha-santonin and sclareol by Botrytis cinerea; Farooq A et al.; Two cytotoxic terpenes, alpha-santonin (1) and sclareol (3) were biotransformed by a plant pathogenic fungus Botrytis cinerea to produce oxidized metabolites in high yields . Alpha-Santonin (1) on fermentation with the fungus for ten days afforded a hydroxylated metabolite identified as 11beta-hydroxy-alpha-santonin (2) in a high yield (83%), while sclareol (3) was metabolized to epoxysclareol (4) (64%) and a new compound 8-deoxy-14,15-dihydro-15-chloro-14-hydroxy-8,9-dehydrosclareol (5) (7%), representing a rare example of microbial halogenation. Wien Klin Wochenschr, 2000 Oct 13, 112(19), 846 - 50 Nontoxigenic sorbitol-fermenting Escherichia coli O157:H- associated with a family outbreak of diarrhoea; Allerberger F et al.; A recent study from Germany reported the isolation of E . coli O157:H7/H- from patients with non-bloody diarrhoea and hemolytic uremic syndrome, questioning the role of Shiga toxin as the main trait of virulence for human disease . We isolated 6 sorbitol-fermenting E . coli O157:H- strains that do not contain Shiga toxin genes . The isolates originated from an outbreak (3 patients, 3 asymptomatic contacts) of non-bloody diarrhoea affecting two families sharing one household . Two children (age 10 months and 2 years) suffered severe diarrhoea over 30 and 10 days, respectively . Their uncle had moderate diarrhoea for 2 weeks . In contrast to the other isolates, the uncle's strain (EH109) did not harbour a chromosomal eae gene encoding gamma-intimin nor the plasmid gene E-hly; it also showed a PFGE pattern that was different from the unique pattern of the other isolates . Employing PFGE, phage typing, and P-gene typing, five of the six stx negative isolates were indistinguishable from the stx 2 positive "Bavarian outbreak strain" . The only human serum tested, obtained from one asymptomatic contact, contained antibodies to the O157 lipopolysaccharide antigen . Our finding of five stx negative sorbitol-fermenting E . coli O157:H- isolates (harbouring eae and E-hly) associated with an outbreak of non-bloody diarrhoea supports the hypothesis that Stx production is not obligatory for the pathogenicity of E . coli O157 for humans. Appl Environ Microbiol, 2000 Dec, 66(12), 5524 - 6 Bacterial toxin-antitoxin gene system as containment control in yeast cells; Kristoffersen P et al.; The potential of a bacterial toxin-antitoxin gene system for use in containment control in eukaryotes was explored . The Escherichia coli relE and relB genes were expressed in the yeast Saccharomyces cerevisiae . Expression of the relE gene was highly toxic to yeast cells . However, expression of the relB gene counteracted the effect of relE to some extent, suggesting that toxin-antitoxin interaction also occurs in S . cerevisiae . Thus, bacterial toxin-antitoxin gene systems also have potential applications in the control of cell proliferation in eukaryotic cells, especially in those industrial fermentation processes in which the escape of genetically modified cells would be considered highly risky. Appl Environ Microbiol, 2000 Dec, 66(12), 5348 - 52 Isolation, purification, and characterization of a killer protein from Schwanniomyces occidentalis; Chen WB et al.; The yeast Schwanniomyces occidentalis produces a killer toxin lethal to sensitive strains of Saccharomyces cerevisiae . Killer activity is lost after pepsin and papain treatment, suggesting that the toxin is a protein . We purified the killer protein and found that it was composed of two subunits with molecular masses of approximately 7.4 and 4.9 kDa, respectively, but was not detectable with periodic acid-Schiff staining . A BLAST search revealed that residues 3 to 14 of the 4.9-kDa subunit had 75% identity and 83% similarity with killer toxin K2 from S . cerevisiae at positions 271 to 283 . Maximum killer activity was between pH 4.2 and 4.8 . The protein was stable between pH 2.0 and 5.0 and inactivated at temperatures above 40 degrees C . The killer protein was chromosomally encoded . Mannan, but not beta-glucan or laminarin, prevented sensitive yeast cells from b