J Biol Chem, 1999 Dec 10, 274(50), 35950 - 4 Amplification of signaling activity of the arc two-component system of Escherichia coli by anaerobic metabolites . An in vitro study with different protein modules; Georgellis D et al.; In Escherichia coli, changes in redox condition of growth are sensed and signaled by the Arc two-component system . This system consists of ArcB as the membrane-associated sensor kinase and ArcA as the cytoplasmic response regulator . ArcB is a tripartite kinase, possessing a primary transmitter, a receiver, and a secondary transmitter domain that catalyzes the phosphorylation of ArcA via a His --> Asp --> His --> Asp phosphorelay, as well as the dephosphorylation of ArcA-P by a reverse phosphorelay . When ArcA and ArcB were incubated with ATP, the peak levels of phosphorylated proteins increased in the presence of the fermentation metabolites D-lactate, acetate, or pyruvate . In this study, we report that these effectors accelerate the autophosphorylation activity of ArcB and enhance the transphosphorylation of ArcA, but have no effect on the dephosphorylation of ArcA-P . Moreover, the presence of the receiver domain of ArcB is essential for the effectors to influence the autophosphorylation rate of the primary transmitter domain of ArcB. Biotechnol Prog, 1999 Nov-Dec, 15(6), 1095 - 105 An integrated process for biomolecule isolation and purification; Dai XP et al.; Biomolecule isolation and purification from a fermentation broth usually involve centrifugation, filtration, adsorption, and chromatography steps . Each step contributes to the product cost and product loss . In this research, a cyclic process integrating commercially available ultrafiltration membranes and chromatographic resin beads was developed to achieve the same goal in one device . The device consisted of ion exchange beads on the shell side of a hollow fiber ultrafiltration module . Loading of proteins on the stationary phase on the shell side was carried out for a period of 5-20 min from the permeate on the shell side produced from tube-side feed in ultrafiltration . The eluent was then introduced either from the shell-side inlet or tube-side inlet; the chromatographic fractions were collected from the shell-side outlet . The column was regenerated/washed next to start a new cycle . Systems studied in this cyclic process include the following binary mixtures: myoglobin and beta-lactoglobulin; hemoglobin and bovine serum albumin; and myoglobin and alpha-lactalbumin . Excellent resolutions of the proteins were obtained . A yeast-based cellular suspension containing a mixture of myoglobin and alpha-lactalbumin was also applied to this device . The target proteins were recovered and purified successfully . The cyclic process-based device integrates clarification, concentration, and chromatographic purification of biomolecules and is suitable for both extracellular and intracellular products. J Appl Microbiol, 1999 Oct, 87(4), 511 - 9 Production of Aspergillus xylanase by lignocellulosic waste fermentation and its application; Gawande PV et al.; Strains of Aspergillus terreus and A . niger, known to produce xylanase with undetectable amounts of cellulase, were studied for xylanase (EC 3.2.1.8) production on various lignocellulosic substrates using solid state fermentation . Of the lignocellulosic substrates used, wheat bran was the best for xylanase production . The effects of various parameters, such as moistening agent, level of initial moisture content, temperature of incubation, inoculum size and incubation time, on xylanase production were studied . The best medium for A . terreus was wheat bran moistened with 1:5 Mandels and Strenberg mineral solution containing 0.1% tryptone, at 35 degrees C, and at inoculum concentration 2x107-2x108 spores 5 g-1 substrate; for A . niger, the best medium was wheat bran moistened with 1:5 Mandels and Strenberg mineral solution containing 0.1% yeast extract, at 35 degrees C, and at an inoculum concentration of 2x107-2x108 spores 5 g-1 substrate . Under these conditions, A . terreus produced 68.9 IU ml-1 of xylanase, and A . niger, 74.5 IU ml-1, after 4 d of incubation . A crude culture filtrate of the two Aspergillus strains was used for the hydrolysis of various lignocellulosic materials . Xylanase preparations from the two strains selectively removed the hemicellulose fraction from all lignocellulosic materials tested. Eur J Biochem, 1999 Dec, 266(3), 1158 - 65 Biochemical and molecular characterization of the {NiFe} hydrogenase from the hyperthermophilic archaeon, Thermococcus litoralis; Rakhely G et al.; Thermococcus litoralis is a hyperthermophilic archaeon that grows at temperatures up to 98 degrees C by fermentative metabolism and reduces elemental sulfur (S0) to H2S . A {NiFe} hydrogenase, responsible for H2S or H2 production, has been purified and characterized . The enzyme is composed of four subunits with molecular mass 46, 42, 34 and 32 kDa . Elemental analyses gave approximate values of 22 Fe, 22 S and 1 Ni per hydrogenase . EPR spectra at 70 and 5 K indicated the presence of four or five {4Fe-4S} and one {2Fe-2S} type clusters . The optimal temperature for both H2 evolution and oxidation, using artificial electron carriers, was around 80 degrees C . The operon encoding the T . litoralis enzyme is composed of four genes forming one transcriptional unit, and transcription is not regulated by S0 . An unusual transcription-initiation site is located 139 bp upstream from the translational start point . Sequence analyses indicated the presence of new putative nucleotide-binding domains . Upstream from the hydrogenase operon, ORFs probably encoding a molybdopterin oxidoreductase enzyme have been identified . Based on sequence, biochemical and biophysical analyses, a model of the enzyme and the pathway of electron flow during catalysis is proposed. J Antibiot (Tokyo), 1999 Aug, 52(8), 689 - 94 Roselipins, inhibitors of diacylglycerol acyltransferase, produced by Gliocladium roseum KF-1040; Tomoda H et al.; Gliocladium roseum KF-1040, a marine isolate, was found to produce a series of new inhibitors of diacylglycerol acyltransferase (DGAT) . Four active compounds, designated roselipins 1A, 1B, 2A and 2B, were isolated from the fermentation broth of the producing strain by solvent extraction, ODS column chromatography and preparative HPLC . The highest production of roselipins was observed when cultured in the medium containing natural sea water . Roselipins inhibit DGAT activity with IC50 values of 15 approximately 22 microM in an enzyme assay system using rat liver microsomes. Atherosclerosis, 2000 Jan, 148(1), 67 - 73 Inhibitory effect of Chinese green tea on endothelial cell-induced LDL oxidation; Yang TT et al.; Green tea has been shown to inhibit Cu(2+)-induced LDL oxidation and suppress lipoxygenase activity . Since LDL oxidation is a characteristic feature of atherogenesis and lipoxygenase is involved in the disease process, the effect of Lung Chen Tea, a non-fermented Chinese green tea, on LDL oxidation induced by human umbilical cord vascular endothelial cell was investigated in the present study . Lung Chen Tea was extracted with methanol and the dried powder was redissolved in water before extraction with chloroform and then ethyl acetate . Lung Chen Tea, chloroform and ethyl acetate fractions dose-dependently reduced LDL oxidation and decreased its relative electrophoretic mobility (P<0.001) when compared to the oxidized LDL . The lipid peroxidation products, thiobarbituric acid reactive substances, and cellular cholesterol were also significantly lowered by 5 and 10 microg/ml Lung Chen Tea (P<0.001) in a dose-dependent manner . The remaining aqueous layer, which was devoid of catechins after chloroform and ethyl acetate extractions, did not prevent LDL oxidation . The results of this study demonstrated that Lung Chen Tea and catechin-rich fractions significantly prevented endothelial cell induced LDL oxidation . The consumption of Lung Chen Tea may therefore lower the risk of coronary heart diseases. Bioorg Med Chem, 1999 Oct, 7(10), 2163 - 8 Novel screening methods--the key to cloning commercially successful biocatalysts; Taylor SJ et al.; Providing sufficient biocatalyst to support the demands of multi tonne product supply can be problematical . Here we describe how screening for and cloning a gamma-lactamase overcame biocatalyst supply issues, and greatly improved the actual biocatalytic process . The isolation of an expressing gamma-lactamase clone from a gene library necessitated a combination of classical molecular biology techniques together with innovative screening methods to identify a functional clone . Once isolated the enzyme was characterised with regard to its process performance and proved to be active at 500 g L(-1) substrate . Further development of the recombinant fermentation and downstream processing has resulted in the ability to produce sufficient biocatalyst from one 5001 fermentation to resolve 5 metric tonnes of (+/-)-lactam, whilst simplifying the process chemistry greatly. Biotechnol Bioeng, 1999, 66(4), 203 - 10 Effect of organic acids on the growth and fermentation of ethanologenic Escherichia coli LY01; Zaldivar J et al.; Hemicellulose residues can be hydrolyzed into a sugar syrup using dilute mineral acids . Although this syrup represents a potential feedstock for biofuel production, toxic compounds generated during hydrolysis limit microbial metabolism . Escherichia coli LY01, an ethanologenic biocatalyst engineered to ferment the mixed sugars in hemicellulose syrups, has been tested for resistance to selected organic acids that are present in hemicellulose hydrolysates . Compounds tested include aromatic acids derived from lignin (ferulic, gallic, 4-hydroxybenzoic, syringic, and vanillic acids), acetic acid from the hydrolysis of acetylxylan, and others derived from sugar destruction (furoic, formic, levulinic, and caproic acids) . Toxicity was related to hydrophobicity . Combinations of acids were roughly additive as inhibitors of cell growth . When tested at concentrations that inhibited growth by 80%, none appeared to strongly inhibit glycolysis and energy generation, or to disrupt membrane integrity . Toxicity was not markedly affected by inoculum size or incubation temperature . The toxicity of all acids except gallic acid was reduced by an increase in initial pH (from pH 6.0 to pH 7.0 to pH 8.0) . Together, these results are consistent with the hypothesis that both aliphatic and mononuclear organic acids inhibit growth and ethanol production in LY01 by collapsing ion gradients and increasing internal anion concentrations . Biotechnol Bioeng, 1999, 66(3), 195 - 201 Rapid quantitation and monitoring of plasmid DNA using an ultrasensitive DNA-binding dye; Noites IS et al.; A sensitive fluorescence-based method for monitoring plasmid DNA during production was investigated . This simple method of assaying for plasmid DNA allows rapid monitoring of plasmid yields from a recombinant Escherichia coli fed-batch fermentation . The assay has several advantages over traditional methods of plasmid DNA measurement . The fluorescent dye is highly specific and can measure total plasmid DNA concentration in about 5 min . The assay is sensitive over a wide range of plasmid concentrations of between 15 and 280 ng/mL, even in the presence of impurities that occur within alkaline lysate preparations . The technique can also be applied to monitoring fermentation and downstream purification steps . Chem Pharm Bull (Tokyo), 1999 Jul, 47(7), 1032 - 4 Futalosine and its derivatives, new nucleoside analogs; Hosokawa N et al.; Futalosine, a new nucleoside analog, was isolated from a fermentation broth of Streptomyces sp . MK359-NF1 . Some chemical derivatives of futalosine were prepared . 6-O-Methylfutalosine methylester inhibited growth of HeLa-S3 cells in vitro (IC50 = 19.5 micrograms/ml) in contrast to the weak activity of futalosine . 6-O-Methylfutalosine methylester at concentrations higher than 10 micrograms/ml inhibited incorporation of 3H-TdR and 3H-UR but not 3H-Leu in the acid-soluble fractions of HeLa-S3 cells. Dent Clin North Am, 1999 Oct, 43(4), 615 - 33 Diet and dental caries; Jensen ME; Dental caries is a diet-related disease that continues to be a problem for certain dental patients . Frequent consumption of fermentable carbohydrates that have low oral clearance rates increases the risk for enamel caries and perhaps is even more dangerous for root surfaces . Highly acidogenic snack foods should be consumed at mealtimes to reduce the risk, and between-meal snacks should be either nonacidogenic (such as xylitol products) or hypoacidogenic (such as sorbitol and HSH products) . Cheeses present a naturally occurring situation that may provide anticariogenic effects from the diet . Certain additives as well as sugar substitutes show great promise for the provision of between-meal snack foods that reduce the risk of dental caries . The dental team should thoroughly understand the relationship of diet to caries and conscientiously apply that knowledge to educate the patients in general as well as counsel specific high-risk individuals . Further emphasis should be placed on the acquisition of sound scientific data for counseling caries patients concerning diet and dental caries. Plant Foods Hum Nutr, 1999, 53(4), 367 - 80 The effect of processing on total organic acids content and mineral availability of simulated cassava-vegetable diets; Adewusi SR et al.; Changes in pH, titratable acidity and mineral content (Ca, Fe, Mg, Zn) were estimated in processed cassava products while the mineral content of raw and blanched amaranthus vegetable was determined . pH of fresh cassava (6.5) decreased as total organic acid (0.07%) increased with fermentation period . Fufu and lafun had the lowest pH and the highest total organic acids contents . Fermentation of cassava increased the total calcium and iron contents, reduced magnesium level while zinc remained fairly constant in grated cassava but was reduced when soaked in water (for the preparation of fufu and lafun) . Fermentation also increased the availability of these selected minerals in both cassva products and simulated cassava-vegetable diets . Blanching reduced the mineral content of amaranthus vegetable but increased mineral availability . Fermentation of cassava and blanching of vegetables play an important role in making minerals more available and these processing methods should be encouraged to potentially ameliorate the disease states associated with mineral deficiency. Plant Foods Hum Nutr, 1999, 53(4), 285 - 96 Effect of blanching time and salt concentration on pectolytic enzymes, texture and acceptability of fermented green beans; Mnkeni AP et al.; Effect of blanching time, salt concentration and fermentation on texture of green beans (var . Tuf) was determined . Beans were blanched at 90 degrees C for 1, 10 or 20 minutes and fermented with brine containing 3.08 and 4.6% salt (corresponding to 1.2 and 1.8% salt in the finished product) . The beans were assessed for texture mechanically using Universal Testing Machine (Model 1011, Instron) . Sensory evaluation was carried out to assess the taste, texture and overall acceptability of the products . Pectolytic enzyme (pectinestarase and exopolygalacturonase) activities were determined in fresh and fermented beans . Increase in blanching time improved the texture significantly . Significant (p<0.05) decreases in shearing energy of the beans were observed in the first two days of fermentation and, thereafter, there were no significant (p>0.05) changes except for samples blanched for one minute . Salt concentration showed a small but significant effect on texture only in samples blanched for one minute and this was probably due to activation by salt of residual pectolytic enzymes in the beans . Most acceptable beans were those blanched for 20 minutes and fermented with 1.2% salt brine. Khirurgiia (Mosk), 1999, (10), 13 - 5 {Debatable questions of surgical sepsis treatment and diagnosis}; Reshetnikov EA et al.; On the basis of critical analysis of the results of combined treatment of 73 patients, the authors suggested that sepsis could be diagnosed only in the presence of systemic inflammatory response, multiorganic insufficiency and obligatory isolation of hemoculture . The microorganisms' specimen from the infected area and the blood are not identical both in primary and repeated inoculation . Impossibility to verify the pathogenic microorganism in the blood prevents from carrying out adequate and purposeful treatment . The absence of correlation between the severity of clinical course of sepsis, microflora species and laboratory immunography data, confirms the opinion that the organism responds to the inflammatory process by complex general physiologic reaction of defence, which includes, besides immunologic system, fermentative, endocrine, vegetative and other systems of homeostasis. J Microbiol Methods, 2000 Jan, 39(2), 121 - 6 A polymerase chain reaction based method for detecting Mycoplasma/Acholeplasma contaminants in cell culture; Tang J et al.; A detection system that utilizes a primer mixture in a nested polymerase chain reaction for detecting Mycoplasma contaminants in cell cultures is described . Primers were designed to amplify the spacer regions between the 16S and 23S ribosomal RNA genes of Mycoplasma and Acholeplasma . This detection system was able to detect 20-180 colony forming units per milliliter of sample . Eight commonly encountered Mycoplasma and Acholeplasma contaminants, which include Mycoplasma (M.) arginini, M . fermentans, M . hominis, M . hyorhinis, M . orale, M . pirum, M . salivarium, and Acholeplasma laidlawii, were consistently amplified . Mycoplasma contaminants generated a single DNA band of 236-365 base pairs (bp), whereas A . laidlawii produced a characteristic two-band pattern of 426 and 219 bp amplicons . Species identification could be achieved by size determination and restriction enzyme digestion . Minor cross-reactions were noted with a few closely related gram positive bacteria and DNA from rat cell lines . A Mycoplasma Detection Kit for detecting Mycoplasma contaminants in cell cultures has been developed based on this approach. J Dairy Sci, 1999 Nov, 82(11), 2486 - 96 Influence of carbohydrate source and buffer on rumen fermentation characteristics, milk yield, and milk composition in early-lactation Holstein cows; Kennelly JJ et al.; The effects of concentrate to forage ratio and sodium bicarbonate (buffer) supplementation on intake, ruminal fermentation characteristics, digestibility coefficients, milk yield, and milk composition were examined in 4 cannulated Holstein cows (100 +/- 20 d in milk) . A 4 x 4 Latin square design with 2 x 2 factorial arrangement of treatments was implemented for 3-wk experimental periods . The 4 treatments were a 50:50 concentrate to forage ratio with 1.2% of dry matter (DM) and without added buffer and a 75:25 concentrate to forage ratio with (1.2% of DM) and without (0% of DM) buffer . The forage component of the ration was a 50:50 mixture of alfalfa and barley and triticale silage, and diets were fed ad libitum as a total mixed ration . Although feed intake was not influenced by treatments, substantial treatment differences were observed for milk yield and milk composition . Cows fed high-concentrate diet had lower ruminal pH, ruminal acetate, and butyrate concentrations, whereas propionate concentrations were significantly elevated . The addition of buffer, at both levels of concentrate inclusion, resulted in elevated total volatile fatty acids and acetate concentrations . We concluded that altering the forage concentrate ratio in the diet of lactation cows influenced milk yield and milk composition, but the addition of buffer to the diet prevented the elevation in trans-C18:1 fatty acids in milk fat, and related milk fat depression, associated with feeding high-concentrate diets. J Dairy Sci, 1999 Nov, 82(11), 2472 - 85 Effect of feeding macerated alfalfa silage on nutrient digestibility and milk yield in lactating dairy cows; Broderick GA et al.; Five feeding studies were conducted with 141 lactating Holstein cows comparing macerated and control alfalfa silage harvested at two cuttings in each of 2 yr . Overall, silage made from macerated alfalfa contained more ash (suggesting improved soil contamination); greater fiber and lower nonprotein nitrogen (NPN) content suggested greater fermentation in the silo . In a digestion study, two diets were fed containing {dry matter (DM) basis} 72% of either control or macerated second-cutting alfalfa . Apparent digestibility of neutral detergent fiber and acid detergent fiber (ADF) was increased by maceration, and similar changes in digestibility were observed with Yb or indigestible ADF as marker; indigestible ADF was used as a marker in later studies . Lactation trials were conducted with first- and second-cutting alfalfa from each year . In each study, diets were formulated from alfalfa silage plus concentrate based on processed high moisture ear corn; mean compositions were (DM basis): negative control (61% control alfalfa silage), macerated (61% macerated alfalfa silage), and positive control (50% control alfalfa silage) . All diets contained 2% crude protein from either roasted soybeans or low-solubles fish meal; soybean meal was added to make the positive control isonitrogenous (but not equal in ruminal undergraded protein) . Milk yield was greater on macerated than negative control in two of four trials but not different in the other two trials . Yields of milk and milk components were not different between macerated and positive control in one of four trials . Versus the negative control, milk fat synthesis was depressed on macerated alfalfa in one trial . Overall performance on macerated versus negative control indicated greater apparent digestibility of organic matter (OM), greater yield of milk, protein, and solids not fat, but lower milk fat content . Yields of milk and milk components were greater overall on positive control versus macerated . Estimation of net energy for lactation (NEL) from maintenance, milk yield, and body weight gain indicated that control and macerated alfalfa silage contained, respectively, 1.36 and 1.42 Mcal of NEL of OM, an increase of about 5% due to maceration of alfalfa in these trials. Eksp Klin Farmakol, 1999 Sep-Oct, 62(5), 59 - 62 {The antioxidant effects of amtizol and trimetazidine}; Smirnov AV et al.; Experiments were conducted on rats to study the antioxidant effects of amtisol and trimethasidin (25 mg/kg) in incomplete cerebral ischemia complicated by hypoxia . Amtisol as well as trimethasidin inhibited activation of lipid peroxidation (LPO) and prevented decrease in activity of the antioxidant system . In in vitro experiments amtisol and trimethasidin blocked epinephrine auto-oxidation . Amtisol inhibited ascorbate-dependent LPO in the liposomes and metabolizing model system, inhibited fermentative NADP-dependent POL in brain tissue homogenates. J Bacteriol, 1999 Dec, 181(23), 7228 - 34 Sulfate transport in Penicillium chrysogenum: cloning and characterization of the sutA and sutB genes; van de Kamp M et al.; In industrial fermentations, Penicillium chrysogenum uses sulfate as the source of sulfur for the biosynthesis of penicillin . By a PCR-based approach, two genes, sutA and sutB, whose encoded products belong to the SulP superfamily of sulfate permeases were isolated . Transformation of a sulfate uptake-negative sB3 mutant of Aspergillus nidulans with the sutB gene completely restored sulfate uptake activity . The sutA gene did not complement the A . nidulans sB3 mutation, even when expressed under control of the sutB promoter . Expression of both sutA and sutB in P . chrysogenum is induced by growth under sulfur starvation conditions . However, sutA is expressed to a much lower level than is sutB . Disruption of sutB resulted in a loss of sulfate uptake ability . Overall, the results show that SutB is the major sulfate permease involved in sulfate uptake by P . chrysogenum. Appl Microbiol Biotechnol, 1999 Oct, 52(4), 608 - 11 Fixation of spent Saccharomyces cerevisiae biomass for lead sorption; Ashkenazy R et al.; Spent Saccharomyces cerevisiae cells from a beer fermentation process were evaluated for lead cation sorption . The crude biomass was washed with water and acetone prior to any other treatment . Although the washed biomass showed substantial lead ion sorption it was susceptible to microbial spoilage . Different aldehydes were tested as chemical fixation agents; however, most of them caused drastic lowering of the metal uptake capacity . However, benzaldehyde was not only an excellent fixation agent, but the biomass treated with it also retained its original lead sorption capacity . A mechanism for the fixation process is suggested. Appl Microbiol Biotechnol, 1999 Oct, 52(4), 534 - 40 Independent production of two molecular forms of a recombinant Rhizopus oryzae lipase by KEX2-engineered strains of Saccharomyces cerevisiae; Takahashi S et al.; A mixture of rProROL having the full-length prosequence (97 amino acids) for a recombinant lipase of Rhizopus oryzae (rROL) and r28ROL having 28 amino acids of the same prosequence has been produced as active forms by Saccharomyces cerevisiae {Takahashi et al . (1998) J Ferment Bioeng 86: 164-168} . However, the separation of rProROL and r28ROL has not been successful due to their identical behavior on column chromatographs, presumably because of the similarity of their surface properties . The independent production of two different molecular forms of rROL was carried out using KEX2-engineered strains of S . cerevisiae, since r28ROL was predicted to be a product from rProROL by a Kex2-like protease . rProROL was successfully obtained by expression of the ROL gene in the S . cerevisiae kex2 strain in which the KEX2 gene encoding Kex2p was disrupted, while r28ROL was obtained by co-expression of the gene (KEX2 delta 613) encoding the soluble form of the C-terminal truncated Kex2 protease (sKex2p) . The specific lipase activities of rProROL and r28ROL were 92.9 U/mg and 140 U/mg, respectively . rProROL was stable at pH 2.2-8.0, and showed the optimal reaction temperature to be 30-35 degrees C with a T50 of 55 degrees C (T50 is the temperature resulting in 50% loss of activity) . The values for r28ROL were pH 3.0-10.0, 25-30 degrees C, and 40 degrees C, respectively . rProROL was an N-linked glycosylated form, but r28ROL was not . The enhanced thermostability of rProROL did not seem to be due to the N-linked glycosylation, as judged by the results of the Endo H treatment . rProROL had the highest esterase activity toward p-nitrophenyl laurate (C12), whereas r28ROL had the highest esterase activity toward p-nitrophenyl caprylate (C8) and stearate (C18) . These results suggest that the distinct properties of these two forms of lipase are caused by the different length of the ROL prosequence. Appl Microbiol Biotechnol, 1999 Oct, 52(4), 502 - 7 Monitoring of low concentrations of glucose in fermentation broth; Nandakumar MP et al.; A highly sensitive glucose sensor, operating in flow-injection analysis (FIA) mode, was developed for the detection of glucose in fermentation broth . The assay system is based upon the post-column reaction of the peroxide formed in the glucose-oxidase-catalysed reaction and subsequent spectrophotometric detection of the coloured product formed . The sensor system was characterised and calibrated using standard solutions, and later used for quantification of glucose in fermentation media . Two types of enzyme column were used: one operated in packed-bed mode and the other in expanded-bed mode . Both columns were integrated into a FIA system and were found to give good analytical results . Glucose concentrations as low as 0.1 mg/l and 5 mg/l could be detected in packed- and expanded-bed modes respectively . Glucose concentrations were measured during typical fed-batch fermentation conditions in this system, and the results are presented. J Agric Food Chem, 1999 Feb, 47(2), 633 - 6 Total antioxidant capacity of teas by the ferric reducing/antioxidant power assay; Benzie IF et al.; This study aimed to compare in vitro antioxidant power of different types of tea (Camellia sinensis) . The ferric reducing/antioxidant power (FRAP) assay was used to measure the total antioxidant power of freshly prepared infusions of 25 types of teas . Results showed that different teas had widely different in vitro antioxidant power and that the antioxidant capacity was strongly correlated (r = 0 . 956) with the total phenolics content of the tea . Expressed as micromol of antioxidant power/g of dried tea leaves, values ranged as 132-654 micromol/g for black ("fermented") teas, 233-532 micromol/g for Oolong ("semifermented") teas, and 272-1144 micromol/g for green ("nonfermented") teas . One cup of tea of usual strength (1-2%), therefore, can provide the same potential for improving antioxidant status as around 150 mg of pure ascorbic acid (vitamin C). Infect Immun, 1999 Dec, 67(12), 6303 - 8 Induction of cytokines and chemokines in human monocytes by Mycoplasma fermentans-derived lipoprotein MALP-2; Kaufmann A et al.; Bacterial infections are characterized by strong inflammatory reactions . The responsible mediators are often bacterially derived cell wall molecules, such as lipopolysaccharide or lipoteichoic acids, which typically stimulate monocytes and macrophages to release a wide variety of inflammatory cytokines and chemokines . Mycoplasmas, which lack a cell wall, may also stimulate monocytes very efficiently . This study was performed to identify mycoplasma-induced mediators . We investigated the induction of cytokines and chemokines in human monocytes exposed to the Mycoplasma fermentans-derived membrane component MALP-2 (macrophage-activating lipopeptide 2) by dose response and kinetic analysis . We found a rapid and strong MALP-2-inducible chemokine and cytokine gene expression which was followed by the release of chemokines and cytokines with peak levels after 12 to 20 h . MALP-2 induced the neutrophil-attracting CXC chemokines interleukin-8 (IL-8) and GRO-alpha as well as the mononuclear leukocyte-attracting CC chemokines MCP-1, MIP-1alpha, and MIP-1beta . Production of the proinflammatory cytokines tumor necrosis factor alpha and IL-6 started at the same time as chemokine release but required 10- to 100-fold-higher MALP-2 doses . The data show that the mycoplasma-derived lipopeptide MALP-2 represents a potent inducer of chemokines and cytokines which may, by the attraction and activation of neutrophils and mononuclear leukocytes, significantly contribute to the inflammatory response during mycoplasma infection. Infect Immun, 1999 Dec, 67(12), 6281 - 5 Effect of MALP-2, a lipopeptide from Mycoplasma fermentans, on bone resorption in vitro; Piec G et al.; Mycoplasmas may be associated with rheumatoid arthritis in various animal hosts . In humans, mycoplasma arthritis has been recorded in association with hypogammaglobulinemia . Mycoplasma fermentans is one mycoplasma species considered to be involved in causing arthritis . To clarify which mycoplasmal compounds contribute to the inflammatory, bone-destructive processes in arthritis, we used a well-defined lipopeptide, 2-kDa macrophage-activating lipopeptide (MALP-2) from M . fermentans, as an example of a class of macrophage-activating compounds ubiquitous in mycoplasmas, to study its effects on bone resorption . MALP-2 stimulated osteoclast-mediated bone resorption in murine calvaria cultures, with a maximal effect at around 2 nM . Anti-inflammatory drugs inhibited MALP-2-mediated bone resorption by about 30% . This finding suggests that MALP-2 stimulates bone resorption partially by stimulating the formation of prostaglandins . Since interleukin-6 (IL-6) stimulates bone resorption, we investigated IL-6 production in cultured calvaria . MALP-2 stimulated the liberation of IL-6, while no tumor necrosis factor was detectable . Additionally, MALP-2 stimulated low levels of NO in calvaria cultures, an effect which was strongly increased in the presence of gamma interferon, causing an inhibition of bone resorption . MALP-2 stimulated the bone-resorbing activity of osteoclasts isolated from long bones of newborn rats and cultured on dentine slices without affecting their number . In bone marrow cultures, MALP-2 inhibited the formation of osteoclasts . It appears that MALP-2 has two opposing effects: it increases the bone resorption in bone tissue by stimulation of mature osteoclasts but inhibits the formation of new ones. Mol Cell Biol, 1999 Dec, 19(12), 7995 - 8002 Mycoplasmal infections prevent apoptosis and induce malignant transformation of interleukin-3-dependent 32D hematopoietic cells; Feng SH et al.; 32D cells, a murine myeloid cell line, rapidly undergo apoptosis upon withdrawal of interleukin-3 (IL-3) supplement in culture . We found that 32D cells, if infected by several species of human mycoplasmas that rapidly activated NF-kappaB, would live and continue to grow in IL-3-depleted culture . Mycoplasma-infected cells showed no evidence of autocrine production of IL-3 . Pyrrolidine dithiocarbamate (PDTC) blocked activation of NF-kappaB and led to prominent cell death . Heat-killed mycoplasmas or mycoplasmal membrane preparations alone could support continued growth of 32D cells in culture without IL-3 supplement for a substantial period of time . However, upon removal of heat-inactivated mycoplasmas, 32D cells quickly became apoptotic . In comparison, live Mycoplasma fermentans or M . penetrans infection for 4 to 5 weeks induced malignant transformation of 32D cells . Transformed 32D cells grew autonomously and no longer required support of growth-stimulating factors including IL-3 and mycoplasmas . The transformed 32D cells quickly formed tumors when injected into nude mice . Karyotyping showed that development of chromosomal changes and trisomy 19 was often associated with malignant transformation and tumorigenicity of 32D cells . Mycoplasmal infections apparently affected the fidelity of genomic transmission in cell division as well as checkpoints coordinating the progression of cell cycle events. Biotechnol Bioeng, 1999, 66(2), 104 - 13 Metabolic shifts by nutrient manipulation in continuous cultures of BHK cells; Cruz HJ et al.; The present work aims at characterizing the regulatory mechanisms of metabolism and product formation of BHK cells producing a recombinant antibody/cytokine fusion protein . This work was carried out through the achievement of several steady-states in chemostat cultures, corresponding to different glucose and glutamine levels in the feed culture medium . Results obtained indicate that both glucose and glutamine consumptions show a Michaelis-Menten dependence on residual glucose and glutamine concentrations, respectively . Similar dependence was also observed for lactate and ammonia productions . K(Glc)(Glc) and K(Gln)(Gln) were estimated to be 0.4 and 0.15 mM, respectively, while q(max)(Glc) and q(max)(Gln) were estimated to be 1.8 and 0.55 nmol 10(-6)cells min(-1), respectively . At very low glucose concentrations, the glucose-to-lactate yield decreased markedly showing a metabolic shift towards lower lactate production; also, the glucose-to-cells yield was increased . At very low-glutamine concentrations, the glutamine-to-ammonia and glutamine-to-cells yields increased, showing a more efficient glutamine metabolism . Overall, amino acid consumption was increased under low glucose or glutamine concentrations . Metabolic-flux analysis confirmed the metabolic shifts by showing increases in the fluxes of the more energetically efficient pathways, at low-nutrient concentrations . No effect of glucose or glutamine concentrations on the cell-specific productivity was observed, even under metabolically shifted metabolism; therefore, it is possible to confine the cells to a more efficient metabolic state maintaining the productivity of the recombinant product of interest, and consequently, increasing final product titers by increasing cell concentration and culture length . This work is intended to be a model approach to characterize cell metabolism in an integrated way; it is highly valuable for the establishment of operating strategies in mammalian cell fermentations in which cell metabolism is to be confined to a desired state . Inflammation, 1999 Dec, 23(6), 495 - 505 Mycoplasma fermentans-induced inflammatory response of astrocytes: selective modulation by aminoguanidine, thalidomide, pentoxifylline and IL-10; Gallily R et al.; Exposure of primary rat glial cells, mostly astrocytes, to heat-inactivated Mycoplasma fermentans triggers the production of tumor necrosis factor alpha (TNFalpha) nitric oxide (NO) and prostaglandin E2 (PGE2) . To attenuate the production of these proinflammatory mediators, four agents: aminoguanidine, pentoxifylline, thalidomide and IL-10 were added to astrocyte cultures . Aminoguanidine (1 and 3 mM), an inhibitor of inducible nitric oxide synthase (iNOS), suppressed the production of the three mediators . TNFalpha was the most sensitive to thalidomide, showing dose-response inhibition at concentrations of 20 microg/ml, 50 microg/ml and 250 microg/ml . PGE2 was affected only by concentrations of 50 microg/ml and 250 microg/ml, whereas NO responded solely to the highest amount of this inhibitor . The cytokine IL-10, at 10 U and 50 U, inhibited only TNFalpha production . Our results imply that selective suppression of proinflammatory mediators by various agents may prove feasible for amelioration of central nervous system inflammatory diseases. Scand J Gastroenterol, 1999 Oct, 34(10), 967 - 73 Ethanol oxidation and acetaldehyde production in vitro by human intestinal strains of Escherichia coli under aerobic, microaerobic, and anaerobic conditions; Salaspuro V et al.; BACKGROUND: Many human colonic facultative anaerobic and aerobic bacteria are capable of alcohol dehydrogenase (ADH)-mediated ethanol oxidation . In this bacteriocolonic pathway for ethanol oxidation intracolonic ethanol is first oxidized by bacterial ADHs to acetaldehyde, which is further oxidized by either colonic mucosal or bacterial aldehyde dehydrogenases to acetate . The produced acetaldehyde is a highly toxic and carcinogenic agent . This study was aimed to investigate the ethanol oxidation capability and acetaldehyde formation of Escherichia coli IH 50546 and IH 50817 . These intestinal E . coli strains expressed either high (IH 50546) or low (IH 50817) ADH activity . METHODS: Strains were cultured for 48 h on agar plates supplemented with ethanol under aerobic, microaerobic (6% O2), and anaerobic conditions . RESULTS: Under aerobic conditions both E . coli strains oxidized ethanol . The ethanol consumption rates (ECR) were 1.046+/-0.025 mM/h and 0.367+/-0.148 mM/h with IH 50546 and IH 50817, respectively . In the case of IH 50546 this was associated with significant acetaldehyde production (418+/-13 microM), suggesting ADH-mediated ethanol oxidation . Under microaerobic conditions only IH 50546 was able to oxidize ethanol (ECR, 0.498+/-0.074 mM/h) and to produce acetaldehyde (up to 440+/-76 microM) to significant extents . Under anaerobic conditions both strains fermented glucose to ethanol . CONCLUSIONS: This study experimentally shows the potential of certain bacteria representing normal human colonic flora to produce acetaldehyde under various atmospheric conditions that may prevail in different parts of the GI tract . This bacterial adaptation may be an essential feature of the bacteriocolonic pathway to produce toxic and carcinogenic acetaldehyde from either endogenous or exogenous ethanol. Gut, 1999 Dec, 45(6), 840 - 7 Wheat bran affects the site of fermentation of resistant starch and luminal indexes related to colon cancer risk: a study in pigs; Govers MJ et al.; BACKGROUND: Recent studies suggest that resistant starch (effective in producing butyrate and lowering possibly toxic ammonia) is rapidly fermented in the proximal colon; the distal colon especially would, however, benefit from these properties of resistant starch . AIMS: To determine whether wheat bran (a rich source of insoluble non-starch polysaccharides), known to hasten gastrointestinal transit, could carry resistant starch through to the distal colon and thus shift its site of fermentation . METHODS: Twenty four pigs were fed four human type diets: a control diet, or control diet supplemented with resistant starch, wheat bran, or both . Intestinal contents and faeces were collected after two weeks . RESULTS: Without wheat bran, resistant starch was rapidly fermented in the caecum and proximal colon . Supplementation with wheat bran inhibited the caecal fermentation of resistant starch, resulting in an almost twofold increase (from 12.9 (2.5) to 20.5 (2.1) g/day, p<0.05) in resistant starch being fermented between the proximal colon and faeces . This resulted in higher butyrate (133%, p<0.05) and lower ammonia (81%, p<0.05) concentrations in the distal colonic regions . CONCLUSIONS: Wheat bran can shift the fermentation of resistant starch further distally, thereby improving the luminal conditions in the distal colonic regions where tumours most commonly occur . Therefore, the combined consumption of resistant starch and insoluble non-starch polysaccharides may contribute to the dietary modulation of colon cancer risk. Trends Biotechnol, 1999 Dec, 17(12), 499 - 505 The development and applications of thermal biosensors for bioprocess monitoring; Ramanathan K et al.; Enzyme thermistors are biosensors that use thermal resistors to measure the heat change caused by an enzymatic reaction . They combine the selectivity of enzymes with the sensitivity of biosensors and allow continuous analysis in a flow-injection mode . They can be used to monitor fermentation systems, biocatalysis, enzyme-catalysed synthesis and clinical and food technology . This article gives an overview of the general principles of enzyme thermistors, the sampling process and the ongoing developments in the field of bioprocess monitoring. Eur J Clin Nutr, 1999 Nov, 53(11), 844 - 8 Comparison of starch digestibility of a blended food prepared with and without extrusion cooking; Meance S et al.; OBJECTIVE: To compare starch digestibility from a maize-soy blended food with and without extrusion cooking . DESIGN: Resistant starch, soluble and insoluble dietary fibres were measured in vitro before and after extrusion . Starch digestibility was assessed in 8 volunteers who took, in a randomised order, a test meal with either 100 g extruded (EF) or non-extruded (NEF) blended flour cooked 15 min at 80 degrees C in 500 ml of water . SETTING: Research ward for healthy volunteers . SUBJECTS: Healthy volunteers . MAIN OUTCOME MEASURES: Starch digestibility was measured by 13C enrichment of breath samples for 8 h . Breath H2 concentration was measured during 12 h to assess bacterial fermentation in the colon . Volunteers reported hunger on a visual scale every hour for 8 h . RESULTS: In vitro resistant starch, soluble and insoluble dietary fibers were higher in NEF than in EF (5.4 vs 1.1, 0.7 vs 0.5, and 13.3 vs 10.4% dw respectively) . In vivo, the area under curve (AUC) for 13CO2 excretion during 8 h was not significantly different for NEF and EF (10.3+/-1.3 vs 9.1+/-0.5 mmol/min, respectively) . AUC for H2 excretion during 12 h was significantly higher for EF than for NEF (26.9+/-5.6 vs 14.1+/-4.7 mL, P<0.05) . AUC for satiety was marginally higher with EF (12.6+/-1.6) than for NEF (10.0+/-2.1) (P=0.06) . CONCLUSIONS: Extrusion cooking does not seem to substantially improve blended foods digestibility . Extrusion of high fibre flours may promote carbohydrate fermentation in the colon and increase satiety. Angew Chem Int Ed Engl, 1999 Nov 2, 38(21), 3197 - 3201 Discovery Through Total Synthesis-Epimerization at C7 in the CP Compounds: Is (7S)-CP-263,114 a Fermentation Product? Meng D, Tan Q, Danishefsky SJ. Sometimes a surprise can occur in a total synthesis . The preparative investigation of the title compound CP-263,114 and of CP-225,917 (1)-both natural products that were first isolated in 1997 by Pfizer-has shown that CP compounds of the 7R series can be converted into the 7S series (for example, 2); (7S)-CP-263,114 is itself apparently a fermentation product. Biotechnol Bioeng, 1999, 66(1), 42 - 50 Steady-state and transient-state analysis of growth and metabolite production in a Saccharomyces cerevisiae strain with reduced pyruvate-decarboxylase activity; Flikweert MT et al.; Pyruvate decarboxylase is a key enzyme in the production of low-molecular-weight byproducts (ethanol, acetate) in biomass-directed applications of Saccharomyces cerevisiae . To investigate whether decreased expression levels of pyruvate decarboxylase can reduce byproduct formation, the PDC2 gene, which encodes a positive regulator of pyruvate-decarboxylase synthesis, was inactivated in the prototrophic strain S . cerevisiae CEN . PK113-7D . This caused a 3-4-fold reduction of pyruvate-decarboxylase activity in glucose-limited, aerobic chemostat cultures grown at a dilution rate of 0.10 h(-1) . Upon exposure of such cultures to a 50 mM glucose pulse, ethanol and acetate were the major byproducts formed by the wild type . In the pdc2Delta strain, formation of ethanol and acetate was reduced by 60-70% . In contrast to the wild type, the pdc2Delta strain produced substantial amounts of pyruvate after a glucose pulse . Nevertheless, its overall byproduct formation was ca . 50% lower . The specific rate of glucose consumption after a glucose pulse to pdc2Delta cultures was about 40% lower than in wild-type cultures . This suggests that, at reduced pyruvate-decarboxylase activities, glycolytic flux is controlled by NADH reoxidation . In aerobic, glucose-limited chemostat cultures, the wild type exhibited a mixed respiro-fermentative metabolism at dilution rates above 0.30 h(-1) . Below this dilution rate, sugar metabolism was respiratory . At dilution rates up to 0.20 h(-1), growth of the pdc2Delta strain was respiratory and biomass yields were similar to those of wild-type cultures . Above this dilution rate, washout occurred . The low micro(max) of the pdc2Delta strain in glucose-limited chemostat cultures indicates that occurrence of respiro-fermentative metabolism in wild-type cultures is not solely caused by competition of respiration and fermentation for pyruvate . Furthermore, it implies that inactivation of PDC2 is not a viable option for reducing byproduct formation in industrial fermentations . Biotechnol Bioeng, 1999, 66(1), 1 - 16 Mathematical modeling and optimization of cellulase protein production using Trichoderma reesei RL-P37; Tholudur A et al.; The enzyme cellulase, a multienzyme complex made up of several proteins, catalyzes the conversion of cellulose to glucose in an enzymatic hydrolysis-based biomass-to-ethanol process . Production of cellulase enzyme proteins in large quantities using the fungus Trichoderma reesei requires understanding the dynamics of growth and enzyme production . The method of neural network parameter function modeling, which combines the approximation capabilities of neural networks with fundamental process knowledge, is utilized to develop a mathematical model of this dynamic system . In addition, kinetic models are also developed . Laboratory data from bench-scale fermentations involving growth and protein production by T . reesei on lactose and xylose are used to estimate the parameters in these models . The relative performances of the various models and the results of optimizing these models on two different performance measures are presented . An approximately 33% lower root-mean-squared error (RMSE) in protein predictions and about 40% lower total RMSE is obtained with the neural network-based model as opposed to kinetic models . Using the neural network-based model, the RMSE in predicting optimal conditions for two performance indices, is about 67% and 40% lower, respectively, when compared with the kinetic models . Thus, both model predictions and optimization results from the neural network-based model are found to be closer to the experimental data than the kinetic models developed in this work . It is shown that the neural network parameter function modeling method can be useful as a "macromodeling" technique to rapidly develop dynamic models of a process . Int J Syst Bacteriol, 1999 Oct, 49 Pt 4, 1631 - 43 Psychrophilic sulfate-reducing bacteria isolated from permanently cold arctic marine sediments: description of Desulfofrigus oceanense gen . nov., sp . nov., Desulfofrigus fragile sp . nov., Desulfofaba gelida gen . nov., sp . nov., Desulfotalea psychrophila gen . nov., sp . nov . and Desulfotalea arctica sp . nov; Knoblauch C et al.; Five psychrophilic, Gram-negative, sulfate-reducing bacteria were isolated from marine sediments off the coast of Svalbard . All isolates grew at the in situ temperature of -1.7 degrees C . In batch cultures, strain PSv29T had the highest growth rate at 7 degrees C, strains ASv26T and LSv54T had the highest growth rate at 10 degrees C, and strains LSv21T and LSv514T had the highest growth rate at 18 degrees C . The new isolates used the most common fermentation products in marine sediments, such as acetate, propionate, butyrate, lactate and hydrogen, but only strain ASv26T was able to oxidize fatty acids completely to CO2 . The new strains had growth optima at neutral pH and marine salt concentration, except for LSv54T which grew fastest with 1% NaCl . Sulfite and thiosulfate were used as electron acceptors by strains ASv26T, PSv29T and LSv54T, and all strains except PSv29T grew with Fe3+ (ferric citrate) as electron acceptor . Chemotaxonomy based on cellular fatty acid patterns and menaquinones showed good agreement with the phylogeny based on 16S rRNA sequences . All strains belonged to the delta subclass of Proteobacteria but had at least 9% evolutionary distance from known sulfate reducers . Due to the phylogenetic and phenotypic differences between the new isolates and their closest relatives, establishment of the new genera Desulfotalea gen . nov., Desulfofaba gen . nov . and Desulfofrigus gen . nov . is proposed, with strain ASv26T as the type strain of the type species Desulfofrigus oceanense sp . nov., LSv21T as the type strain of Desulfofrigus fragile sp . nov., PSv29T as the type strain of the type species Desulfofaba gelida sp . nov., LSv54T as the type strain of the type species Desulfotalea psychrophila sp . nov . and LSv514T as the type strain of Desulfotalea arctica sp . nov. Nahrung, 1999 Oct, 43(5), 320 - 4 Physico-chemical properties of Azizi' green pickled olives as affected by alkali process; el-Makhzangy A et al.; This work was carried out to study the effect of lye treatment at different concentrations (1.0, 2.0 and 2.5%) on some physical-chemical changes of green table olive 'Azizi' cultivar during fermentation process . Results indicated that lye treatment at 1% and 2% using sodium hydroxide were the more suitable concentration for processing green table olive 'Azizi' cultivar under Egyptian condition, where the quality in texture, colour, flavour and appearance was recorded . Statistical analysis revealed that there were significant differences in pH, NaCl content and acidity of green olive during the fermentation period as affected by lye treatment . A positive correlation was found between the sensorial properties of pickled olives. Mol Med, 1999 Sep, 5(9), 631 - 40 Butyrate switches the pattern of chemokine secretion by intestinal epithelial cells through histone acetylation; Fusunyan RD et al.; BACKGROUND: Butyrate, a fermentation product of intestinal bacteria, modifies chromatin structure through histone acetylation, thereby altering gene transcription . IL-8 and MCP-1 are chemokines, expressed by intestinal epithelial cells, which attract neutrophils and monocytes, respectively . We hypothesized that butyrate may alter IL-8 and MCP-1 expression by intestinal epithelial cells through histone acetylation . MATERIALS AND METHODS: IL-8 and MCP-1 expression was measured by ELISA and RNA transfer blots . Acetylated histones were separated on acetic acid-urea-triton gels . Butyrate was compared to Trichostatin-A, a specific inhibitor of histone deacetylase and to other short chain fatty acids . RESULTS: Caco-2 cells constitutively secreted MCP-1 but not IL-8 . Butyrate reversibly decreased MCP-1 secretion . In contrast, butyrate increased IL-8 production . The effects of butyrate and Trichostatin-A were greater when cells were stimulated with IL-1beta . Butyrate and Trichostatin-A both increased histone acetylation . Trichostatin-A and other short chain fatty acids altered chemokine secretion according to their effect on histone acetylation . CONCLUSIONS: Butyrate reversibly switches chemokine secretion by epithelial cells through histone acetylation . We speculate that butyrate carries information from resident bacteria to epithelial cells . Epithelial cells transduce this signal through histone acetylation, modulating the secretion of chemokines. Planta, 1999 Oct, 209(4), 547 - 50 Poly(beta-hydroxybutyrate) production in oilseed leukoplasts of brassica napus Houmiel KL, Slater S, Broyles D, Casagrande L, Colburn S, Gonzalez K, Mitsky TA, Reiser SE, Shah D, Taylor NB, Tran M, Valentin HE, Gruys KJ. Polyhydroxyalkanoates (PHAs) comprise a class of biodegradable polymers which offer an environmentally sustainable alternative to petroleum-based plastics . Production of PHAs in plants is attractive since current fermentation technology is prohibitively expensive . The PHA homopolymer poly(beta-hydroxybutyrate) (PHB) has previously been produced in leaves of Arabidopsis thaliana (Nawrath et al., 1994, Proc Natl Acad Sci USA 91: 12760-12764) . However, Brassica napus oilseed may provide a better system for PHB production because acetyl-CoA, the substrate required in the first step of PHB biosynthesis, is prevalent during fatty acid biosynthesis . Three enzymatic activities are needed to synthesize PHB: a beta-ketothiolase, an acetoacetyl-CoA reductase and a PHB synthase . Genes from the bacterium Ralstonia eutropha encoding these enzymes were independently engineered behind the seed-specific Lesquerella fendleri oleate 12-hydroxylase promoter in a modular fashion . The gene cassettes were sequentially transferred into a single, multi-gene vector which was used to transform B . napus . Poly(beta-hydroxybutyrate) accumulated in leukoplasts to levels as high as 7.7% fresh seed weight of mature seeds . Electron-microscopy analyses indicated that leukoplasts from these plants were distorted, yet intact, and appeared to expand in response to polymer accumulation. Arch Tierernahr, 1999, 52(1), 75 - 93 {Investigations on the fermentation quality of silage from low-nitrate green forage}; Kaiser E et al.; In 3-year-experiments green forage from Dactylis glomerata and Festuca species, produced by differentiated cutting frequencies, was ensiled under laboratory conditions . The forage was almost without nitrate . Because of the higher content of water-soluble carbohydrates the fermentability coefficients of Festuca species were above of Dactylis glomerata . The fermentability coefficients of both plant species were inferior in the second and third cut, even if the first cut was delayed until July . Despite of similar fermentability coefficients of the two plant species silages contained different amounts of lactic and butyric acid . The portion of lactic acid amounted to 52 to 57% and 60 to 73% of total acids, the proportion of butyric acid 30 to 35% and 18 to 25% for Dactylis glomerata and Festuca species, respectively . According to the high fermentability coefficients silages free of butyric acid would be expected, however, by both species butyric acid always was formed, in some cases at high concentrations . In the contrary the amounts of ammonia, acetic acid and alcohol as well as the pH-value were almost extremely low . It can be concluded that the quality of silages produced of green forages with low nitrate cannot be assessed adequately by the current evaluation key. Arch Tierernahr, 1999, 52(1), 1 - 14 Biochemical characteristics of non starch polysaccharide hydrolyzing enzyme preparations designed as feed additives for poultry and piglet nutrition; Vahjen W et al.; Non starch polysaccharide hydrolyzing enzyme preparations analyzed in this study were composed of up to nine (1-3, 1-4)-beta-glucanase activities and up to six xylanase activities with different molecular weights in the range from 100 kD down to 18 kD as determined with SDS/PAGE zymograms . Partially purified enzyme fractions differed in terms of pH-optima, isoelectric point and thermal stability in aquaeous solutions . Different beta-glucanase activities were found in different production strains, although some enzymes were conserved over genus boundaries . Enzyme preparations from the same or related strains exhibited different patterns of enzyme activity, indicating modification of strain and/or fermentation conditions . Some enzyme preparations contained significant amounts of polygalacturonase and/or galactomannase activity . The pH profiles of whole enzyme preparations resulted from pH optima of isoenzyme fractions . Temperature optima for all preparations were between 50 and 60 degrees C . Thermal stability of high molecular weight components tended to be lower than for low molecular weight fractions . Fractions with cellulase activity were most stable, followed by (1-3, 1-4)-beta-glucanase activities, while fractions with xylanase activities exhibited low thermal stabilities . Incubation of enzyme preparations and their respective active fractions in digesta supernatants revealed only small differences in residual xylanase activity . Digesta from gizzard samples led to the highest inactivation . It is concluded that commercial enzyme preparations display different modes of action and that the development of improved enzyme preparations depends not only on thermal stability, but also on pH profile, substrate specificity and proteolytic stability within the digestive tract. Arch Tierernahr, 1999, 52(2), 195 - 201 Age and incubation time effects on in vitro caecal fermentation pattern in rabbits before and after weaning; Marounek M et al.; The caecal fermentation pattern was studied in four litters of rabbits . Rabbits were sequentially slaughtered at the age of 4 (before weaning), 6, 8 and 11 weeks . Their caecal contents were analyzed and incubated in vitro at 39 degrees C for 6 and 12 h . Net productions of short-chain fatty acids (SCFA), hydrogen and methane were determined . The average caecal weight increased three-times within two weeks after weaning, from 31.4 to 93.7 g . At the end of the experiment, the caecal weight was on average 134.4 g . A large variability of the SCFA concentration observed before weaning decreased after weaning . Measurements of caecal metabolite profiles and results of in vitro experiments indicated a certain decrease of propionate in favour of butyrate, associated with the weaning . The establishment of methanogens in rabbits was slow . Methanogenesis started in one out of four rabbits at the age of 6 weeks . Five weeks later, one of four rabbits still did not produce methane . The hydrogen recovery decreased between the 4th and the 6th week of age, due to the increase of the butyrate/propionate ratio . After the 6th week, the hydrogen recovery increased with age, apparently because of the increase in methane production . Hydrogen recovery tended to increase during incubation, suggesting a decrease of reductive acetogenesis . This increase was observed both in methanogenic and non-methanogenic rabbit caecal cultures . In former cultures, the ratio CH4/SCFA rose with time of incubation. Arch Tierernahr, 1999, 52(2), 167 - 84 {Effect of hay particle size at different concentrations and feeding levels on digestive processes and feed intake in ruminants . 1 . Chewing activity and fermentation in the rumen}; Tafaj M et al.; In order to study the main effects of particle size three ruminally fistulated cows were fed a hay rich in fibre in long (28.7 mm), chopped (9.2 mm) and ground (2.9 mm) form in a 3 x 3 Latin square design . In another three factorial experiment with 8 wethers (4 animals were ruminally fistulated) the main effects and interactions of the above mentioned hay particle size at two concentrate levels (10.4 to 13.3 and 29.5 to 40.1% in the ration) and at two feeding levels (restricted and ad libitum) were investigated . There was no effect of chopped hay (9.2 mm) on chewing activity, whereas ground hay (2.9 mm) reduced rumination time (52% in sheep and 36% in dairy cows) and chewing expense (time/unit of DM or NDF intake) . These effects were more pronounced at high concentrate intake . Sheep increased feed intake more through reduction of rumination expense than through the extension of rumination time . pH-value, concentration of bicarbonate and C2:C3-ratio indicate favourable fermentation conditions in long (28.7 mm) and chopped hay (9.2 mm), whereas a negative influence of ground hay (2.9 mm) or ruminal fermentation could be observed. Biochem J, 1999 Nov 15, 344 Pt 1, 77 - 84 Competition between Escherichia coli strains expressing either a periplasmic or a membrane-bound nitrate reductase: does Nap confer a selective advantage during nitrate-limited growth? Potter LC, Millington P, Griffiths L, Thomas GH, Cole JA. The physiological role of the periplasmic nitrate reductase, Nap, one of the three nitrate reductases synthesized by Escherichia coli K-12, has been investigated . A series of double mutants that express only one nitrate reductase were grown anaerobically in batch cultures with glycerol as the non-fermentable carbon source and nitrate as the terminal electron acceptor . Only the strain expressing nitrate reductase A grew rapidly under these conditions . Introduction of a narL mutation severely decreased the growth rate of the nitrate reductase A strain, but enhanced the growth of the Nap(+) strain . The ability to use nitrate as a terminal electron acceptor for anaerobic growth is therefore regulated primarily by the NarL protein at the level of transcription . Furthermore, the strain expressing nitrate reductase A had a substantial selective advantage in competition with the strain expressing only Nap during nitrate-sufficient continuous culture . However, the strain expressing Nap was preferentially selected during nitrate-limited continuous growth . The saturation constants for nitrate for the two strains (which numerically are equal to the nitrate concentrations at half of the maximum specific growth rate and therefore reflect the relative affinities for nitrate) were estimated using the integrated Monod equation to be 15 and 50 microM for Nap and nitrate reductase A respectively . This difference is sufficient to explain the selective advantage of the Nap(+) strain during nitrate-limited growth . It is concluded that one physiological role of the periplasmic nitrate reductase of enteric bacteria is to enable bacteria to scavenge nitrate in nitrate-limited environments. Biochem J, 1999 Nov 15, 344 Pt 1, 69 - 76 Essential roles for the products of the napABCD genes, but not napFGH, in periplasmic nitrate reduction by Escherichia coli K-12; Potter LC et al.; The seven nap genes at minute 47 on the Escherichia coli K-12 chromosome encode a functional nitrate reductase located in the periplasm . The molybdoprotein, NapA, is known to be essential for nitrate reduction . We now demonstrate that the two c-type cytochromes, the periplasmic NapB and the membrane-associated NapC, as well as a fourth polypeptide, NapD, are also essential for nitrate reduction in the periplasm by physiological substrates such as glycerol, formate and glucose . None of the three iron-sulphur proteins, NapF, NapG or NapH, are essential, irrespective of whether the bacteria are grown anaerobically in the presence of nitrate or fumarate as a terminal electron acceptor, or by glucose fermentation . Mutation of napD resulted in the total loss of Methyl Viologen-dependent nitrate reductase activity of the molybdoprotein, NapA, consistent with an earlier suggestion by others that NapD might be required for post-translational modification of NapA. Nutr Hosp, 1999 May, 14 Suppl 2, 22S - 31S {Dietary fiber: concept, classification and current indications}; Garcia Peris P et al.; Fiber is a concept that refers to or encompasses several carbohydrates and lignine that resist hydrolysis by human digestive enzymes and that are fermented by the microflora of the colon . From a practical point of view, fibers can be divided into soluble and insoluble . There is general acceptance of the concepts soluble fiber, fermentable, viscous and insoluble fiber, and non-viscous and barely fermentable fiber . The physiological effects and therefore the clinical applications of both fibers are different . In general, the insoluble fiber is barely fermentable and has a marked laxative and intestinal regulatory effect . Soluble fiber is fermented to a high degree, showing a powerful trophic effect at the colon level . Soluble fiber is also attributed a positive role in the carbohydrate and lipid metabolism due to the effects that this has at the intestinal and the systemic level on the glucose and the cholesterol metabolism . The goal of this article is to review the current concept of fiber based on the existing bibliography (it is thought that perhaps the current classification should be changed and that fiber should be talked about depending on its degree of polymerization), its physiologic effects and the possible indications that this may have from a clinical point of view, be this at the level of oral or enteral nutrition. J Bacteriol, 1999 Nov, 181(21), 6806 - 13 Role of crotonyl coenzyme A reductase in determining the ratio of polyketides monensin A and monensin B produced by Streptomyces cinnamonensis; Liu H et al.; The ccr gene, encoding crotonyl coenzyme A (CoA) reductase (CCR), was cloned from Streptomyces cinnamonensis C730.1 and shown to encode a protein with 90% amino acid sequence identity to the CCRs of Streptomyces collinus and Streptomyces coelicolor . A ccr-disrupted mutant, S . cinnamonensis L1, was constructed by inserting the hyg resistance gene into a unique BglII site within the ccr coding region . By use of the ermE* promoter, the S . collinus ccr gene was expressed from plasmids in S . cinnamonensis C730 . 1/pHL18 and L1/pHL18 . CCR activity in mutant L1 was shown to decrease by more than 90% in both yeast extract-malt extract (YEME) medium and a complex fermentation medium, compared to that in wild-type C730.1 . Compared to C730.1, mutants C730.1/pHL18 and L1/pHL18 exhibited a huge increase in CCR activity (14- and 13-fold, respectively) in YEME medium and a moderate increase (3.7- and 2 . 7-fold, respectively) in the complex fermentation medium . In the complex fermentation medium, S . cinnamonensis L1 produced monensins A and B in a ratio of 12:88, dramatically lower than the 50:50 ratio observed for both C730.1 and C730.1/pHL18 . Plasmid (pHL18)-based expression of the S . collinus ccr gene in mutant L1 increased the monensin A/monensin B ratio to 42:58 . Labeling experiments with {1, 2-(13)C(2)}acetate demonstrated the same levels of intact incorporation of this material into the butyrate-derived portion of monensin A in both C730.1 and mutant C730.1/pLH18 but a markedly decreased level of such incorporation in mutant L1 . The addition of crotonic acid at 15 mM led to significant increases in the monensin A/monensin B ratio in C730.1 and C730.1/pHL18 but had no effect in S . cinnamonensis L1 . These results demonstrate that CCR plays a significant role in providing butyryl-CoA for monensin A biosynthesis and is present in wild-type S . cinnamonensis C730.1 at a level sufficient that the availability of the appropriate substrate (crotonyl-CoA) is limiting. Nucleic Acids Res, 1999 Nov 15, 27(22), 4391 - 8 Expression of GUT1, which encodes glycerol kinase in Saccharomyces cerevisiae, is controlled by the positive regulators Adr1p, Ino2p and Ino4p and the negative regulator Opi1p in a carbon source-dependent fashion; Grauslund M et al.; In Saccharomyces cerevisiae glycerol utilization is mediated by two enzymes, glycerol kinase (Gut1p) and mitochondrial glycerol-3-phosphate dehydrogenase (Gut2p) . The carbon source regulation of GUT1 was studied using promoter-reporter gene fusions . The promoter activity was lowest during growth on glucose and highest on the non-fermentable carbon sources, glycerol, ethanol, lactate, acetate and oleic acid . Mutational analysis of the GUT1 promoter region showed that two upstream activation sequences, UAS(INO) and UAS(ADR1), are responsible for approximately 90% of the expression during growth on glycerol . UAS(ADR1) is a presumed binding site for the zinc finger transcription factor Adr1p and UAS(INO) is a presumed binding site for the basic helix-loop-helix transcription factors Ino2p and Ino4p . In vitro experiments showed Adr1 and Ino2/Ino4 protein-dependent binding to UAS(ADR1) and UAS(INO) . The negative regulator Opi1p mediates repression of the GUT1 promoter, whereas the effects of the glucose repressors Mig1p and Mig2p are minor . Together, the experiments show that GUT1 is carbon source regulated by different activation and repression systems. J Gastroenterol Hepatol, 1999 Sep, 14(9), 880 - 8 Butyrate from bacterial fermentation of germinated barley foodstuff preserves intestinal barrier function in experimental colitis in the rat model; Kanauchi O et al.; BACKGROUND AND AIMS: The consumption of germinated barley foodstuff (GBF) prevents inflammation and diarrhoea in a colitis model . In this study we investigated the mechanism of the preventative effect of GBF on experimental colitis in rats, in view of production of bacterial butyrate and preservation of intestinal barrier function . METHODS: Sprague-Dawley rats administered with diets supplemented with 3.5% dextran sodium sulphate were used as an experimental colitis model . Butyrate was given to rats orally or intracaecally . Intestinal barrier function was estimated by light microscopic observation of the mucosa, intestinal permeability and bacterial translocation . RESULTS: Mucosal damage was reduced by intracaecal administration of butyrate, but not by oral administration . Bacterial butyrate production and reduction of mucosal damage depended on the dose of GBF in diets . The action of endogenous bacterial butyrate, including the reduction of intestinal permeability and bacterial translocation, was inhibited by administration of an inhibitor of beta-oxidation of short-chain fatty acids . CONCLUSIONS: The feeding of GBF promotes bacterial butyrate production and improves intestinal barrier function in rats, resulting in mitigation of experimental colitis. Can J Vet Res, 1999 Oct, 63(4), 248 - 52 Evaluation of lansoprazole (an H+/K+-ATPase inhibitor) and azithromycin (an antibiotic) for control of gastric ulceration in swine during periods of feed deprivation; Melnichouk S et al.; Helicobacter-like organisms as well as fermentative bacteria have been implicated in gastric ulcer production in swine . Irregular feeding schedules are also considered a major risk factor . A research trial was conducted to determine whether medication with an acid secretion inhibitor (lansoprazole), either alone or in combination with an antibiotic (azithromycin), would protect pigs from gastric ulceration if the animals were subjected to a 48 h period of fasting . In a 2 x 3 factorial design, 48 pigs were fasted, while an equal number were fed ad libitum . Within these 2 study groups, pigs were randomly assigned to 1 of 3 treatments: control, 30 mg lansoprazole s.i.d . for 7 d, or lansoprazole (30 mg s.i.d . for 7 d) and azithromycin (500 mg s.i.d . for 3 d) . Overall, fasted pigs were 1.9 times more likely to develop erosive or ulcerative lesions of the pars esophagea (chi2 = 9.89, P < 0.002) . Treatment with an acid secretion inhibitor alone or in combination with an antibiotic did not protect pigs from developing gastric lesions . Helicobacter-like organisms were not detected in any of the stomachs . Possibly, the lansoprazole dose of 30 mg given once per day was insufficient to prevent pH levels from becoming low enough to cause damage to epithelial tissue . Alternatively other substances such as bile acids may have caused the ulcerative lesions, even though stomach acid production was suppressed. Adv Biochem Eng Biotechnol, 1999, 65, 243 - 80 Production of multifunctional organic acids from renewable resources; Tsao GT et al.; Recently, the microbial production of multifunctional organic acid has received interest due to their increased use in the food industry and their potential as raw materials for the manufacture of biodegradable polymers . Certain species of microorganisms produce significant quantities of organic acids in high yields under specific cultivation conditions from biomass-derived carbohydrates . The accumulation of some acids, such as fumaric, malic and succinic acid, are believed to involve CO2-fixation which gives high yields of products . The application of special fermentation techniques and the methods for downstream processing of products are described . Techniques such as simultaneous fermentation and product recovery and downstream processing are likely to occupy an important role in the reduction of production costs . Finally, some aspects of process design and current industrial production processes are discussed. Adv Biochem Eng Biotechnol, 1999, 65, 163 - 92 Successful design and development of genetically engineered Saccharomyces yeasts for effective cofermentation of glucose and xylose from cellulosic biomass to fuel ethanol; Ho NW et al.; Ethanol is an effective, environmentally friendly, nonfossil, transportation biofuel that produces far less pollution than gasoline . Furthermore, ethanol can be produced from plentiful, domestically available, renewable, cellulosic biomass . However, cellulosic biomass contains two major sugars, glucose and xylose, and a major obstacle in this process is that Saccharomyces yeasts, traditionally used and still the only microorganisms currently used for large scale industrial production of ethanol from glucose, are unable to ferment xylose to ethanol . This makes the use of these safest, most effective Saccharomyces yeasts for conversion of biomass to ethanol economically unfeasible . Since 1980, scientists worldwide have actively been trying to develop genetically engineered Saccharomyces yeasts to ferment xylose . In 1993, we achieved a historic breakthrough to succeed in the development of the first genetically engineered Saccharomyces yeasts that can effectively ferment both glucose and xylose to ethanol . This was accomplished by carefully redesigning the yeast metabolic pathway for fermenting xylose to ethanol, including cloning three xylose-metabolizing genes, modifying the genetic systems controlling gene expression, changing the dynamics of the carbon flow, etc . As a result, our recombinant yeasts not only can effectively ferment both glucose and xylose to ethanol when these sugars are present separately in the medium, but also can effectively coferment both glucose and xylose present in the same medium simultaneously to ethanol . This has made it possible because we have genetically engineered the Saccharomyces yeasts as such that they are able to overcome some of the natural barrier present in all microorganisms, such as the synthesis of the xylose metabolizing enzymes not to be affected by the presence of glucose and by the absence of xylose in the medium . This first generation of genetically engineered glucose-xylose-cofermenting Saccharomyces yeasts relies on the presence of a high-copy-number 2 mu-based plasmid that contains the three cloned genetically modified xylose-metabolizing genes to provide the xylose-metabolizing capability . In 1995, we achieved another breakthrough by creating the super-stable genetically engineered glucose-xylose-cofermenting Saccharomyces yeasts which contain multiple copies of the same three xylose-metabolizing genes stably integrated on the yeast chromosome . This is another critical development which has made it possible for the genetically engineered yeasts to be effective for cofermenting glucose and xylose by continuous fermentation . It is widely believed that the successful development of the stable glucose-xylose-cofermenting Saccharomyces yeasts has made the biomass-to-ethanol technology a step much closer to commercialization . In this paper, we present an overview of our rationales and strategies as well as our methods and approaches that led to the ingenious design and successful development of our genetically engineered Saccharomyces yeasts for effective cofermentation of glucose and xylose to biofuel ethanol. Adv Biochem Eng Biotechnol, 1999, 65, 117 - 61 Genetic engineering for improved xylose fermentation by yeasts; Jeffries TW et al.; Xylose utilization is essential for the efficient conversion of lignocellulosic materials to fuels and chemicals . A few yeasts are known to ferment xylose directly to ethanol . However, the rates and yields need to be improved for commercialization . Xylose utilization is repressed by glucose which is usually present in lignocellulosic hydrolysates, so glucose regulation should be altered in order to maximize xylose conversion . Xylose utilization also requires low amounts of oxygen for optimal production . Respiration can reduce ethanol yields, so the role of oxygen must be better understood and respiration must be reduced in order to improve ethanol production . This paper reviews the central pathways for glucose and xylose metabolism, the principal respiratory pathways, the factors determining partitioning of pyruvate between respiration and fermentation, the known genetic mechanisms for glucose and oxygen regulation, and progress to date in improving xylose fermentations by yeasts. Microbiol Immunol, 1999, 43(7), 711 - 6 Phylogenetic analysis of saccharolytic oral treponemes isolated from human subgingival plaque; Sakamoto M et al.; A total of 74 strains of oral treponemes, which were isolated from subgingival plaque samples from patients with periodontitis, were taxonomically studied on the basis of biochemical characteristics, DNA-DNA hybridization, and 16S rRNA gene sequences . These organisms fermented carbohydrates and required rumen fluid or short-chain volatile fatty acids for growth . The isolates were divided into seven subgroups based on their biochemical characteristics . The levels of DNA relatedness among the representative strains of each subgroup and Treponema socranskii (including three subspecies) were greater than 78%, while the levels of DNA relatedness among these strains and other Treponema species, including T . denticola and "T . vincentii", were less than 15% . DNA-DNA hybridization indicated that all subgroups belonged to T . socranskii . This result correlated well with the cluster on the phylogenetic trees based on 16S rRNA sequences. Alcohol Alcohol, 1999 Sep-Oct, 34(5), 773 - 85 Patterns of alcohol consumption in the Seychelles Islands (Indian Ocean); Perdrix J et al.; Self-reported drinking habits were examined in a random sample of 1067 persons aged 25-64 years in the Seychelles, a country in epidemiological transition where consumption of home-brewed, mostly unregistered beverages has been traditionally high . Alcohol consumption was calculated from respondents reporting at least one drink per week ('regular drinkers') . Among men, 51.1% were regular drinkers and had average intake of 112.1 ml alcohol a day . Among women, 5.9% were regular drinkers and had 49.7 ml alcohol a day . Frequency of drinking, but not amount per drinker, was slightly less in the 25-34-year than older-age categories . Home-brews (mostly palm toddy and fermented sugar cane juice) were consumed by 52% of regular drinkers and accounted for 54% of the total alcohol intake reported by all regular drinkers . Based on the reported consumption by regular drinkers only, the average annual alcohol consumption amounted respectively to 20.7 litres and 1.2 litres per man and woman aged 25-64 years, or, using extrapolation, 13.2 litres and 0.8 litres per man and woman respectively of the total population . These values may underestimate the true figures by half, since reported beer consumption accounted for 53% of beer sales . Socio-economic status was associated strongly and inversely with home-brew consumption, but slightly and positively with consumption of commercially marketed beverages . Alcohol intake was associated with smoking, high-density lipoprotein cholesterol, carbohydrate-deficient transferrin and blood pressure, but not with age and body mass index . In conclusion, these data show high alcohol consumption in the Seychelles with an important gender difference, a large proportion of alcohol derived from home-brews, and opposite tendencies for the relationships between socio-economic status and home-made or commercially marketed beverages. J Food Prot, 1999 Oct, 62(10), 1115 - 22 Occurrence and survival of verocytotoxin-producing Escherichia coli O157 in meats obtained from retail outlets in The Netherlands; Heuvelink AE et al.; In 1996 and 1997, 2,941 fresh and processed meat products obtained from supermarkets and butcher shops in The Netherlands were examined for the presence of verocytotoxin-producing Escherichia coli of serogroup O157 (O157 VTEC) . Additionally, the fate of O157 VTEC in raw meat products stored at low temperatures and the effect of different additives were evaluated . O157 VTEC strains were isolated from 6 (1.1%) of 571 samples of raw minced beef, 2 (0.5%) of 402 samples of raw minced mixed beef and pork, 1 (1.3%) of 76 samples of raw minced pork, 1 (0.3%) of 393 samples of other raw pork products, and 1 (0.3%) of 328 samples of cooked or fermented ready-to-eat meats . Other raw beef products (n = 223) and meat samples originating from poultry (n = 819), sheep or lamb (n = 46), or wild animals (n = 83) were all found to be negative for O157 VTEC . For the survival experiments we used tartaar (minced beef with a fat content of less than 10%) and filet americain (tartaar mixed with a mayonnaise-based sauce {80 to 20%}) . The O157 VTEC strain tested was able to survive in tartaar and filet americain stored at -20, 0, 5, or 7 degrees C for 3 days . At both 7 and at 15 degrees C, O157 VTEC counts in tartaar and filet americain remained virtually unchanged throughout a storage period of 5 days . Addition of acetic acid (to pH 4.0), sodium lactate (1 and 2% {wt/wt}), or components of the lactoperoxidase-thiocyanate-hydrogen peroxide system to filet americain did not result in a reduction of viable O157 VTEC cells during storage at 7 or 15 degrees C . It was concluded that raw meat contaminated with O157 VTEC will remain a hazard even if the meat is held at low or freezing temperatures. Crit Rev Microbiol, 1999, 25(3), 229 - 43 Mycopesticide production by fermentation: potential and challenges; Deshpande MV; The agriculture industry is in need of novel biopesticides and development of large-scale production of mycopesticide, either fungal cells themselves or cell-free fungal components . The identification of a fungal strain with pesticide activity, and its improvement, is the primary step in developing infective propagules such as conidia, blastospores, chlamydospores, oospores, and zygospores as well as in preparing hydrolytic enzyme mixtures . This review discusses various parameters for submerged and solid state fermentation to produce fungal structures, particularly of mycoparasitic and entomopathogenic species that are prospective candidates for use as mycopesticides . The understanding of the molecular aspects of fungus-fungus and fungus-insect interactions, the role of hydrolytic enzymes especially chitinases in the killing process, and the possible use of chitin synthesis inhibitors are the prime areas of research aimed at making fungi more effective either singly or in combination as mycopesticides. J Clin Microbiol, 1999 Nov, 37(11), 3491 - 6 Escherichia coli O157:H7 and O157:H(-) strains that do not produce Shiga toxin: phenotypic and genetic characterization of isolates associated with diarrhea and hemolytic-uremic syndrome; Schmidt H et al.; We have isolated one sorbitol-nonfermenting (SNF) Escherichia coli O157:H7 isolate and five sorbitol-fermenting (SF) E . coli O157:H(-) isolates that do not contain Shiga toxin (Stx) genes (stx) . Isolates originated from patients with diarrhea (n = 4) and hemolytic-uremic syndrome (HUS) (n = 2) . All isolates harbored a chromosomal eae gene encoding gamma-intimin as well as the plasmid genes E-hly and etp . The E . coli O157:H7 isolate was katP and espP positive . Respective sera obtained from the patient with HUS contained antibodies to the O157 lipopolysaccharide antigen . The stx-negative E . coli O157:H7 isolate is genetically related to stx-positive SNF E . coli O157:H7 . All stx-negative SF E . coli O157:H(-) isolates belong to the same genetic cluster and are closely related to stx-positive SF E . coli O157:H(-) isolates . Our data indicate that stx-negative E . coli O157:H7/H(-) variants may occur at a low frequency and cannot be recognized by diagnostic methods that target Stx. Indian J Exp Biol, 1999 Jul, 37(7), 731 - 3 Production of calcium gluconate by fermentation; Tripathi CK et al.; Calcium gluconate production by Aspergillus niger was investigated in shake flask, rolling shaker, air-lift reactor and stirred reactor . Growth pattern of the organism and fermentation conditions determined the yield of the product . High calcium gluconate production was achieved in air-lift reactor with pellet form of cell growth at moderate specific growth rate and biomass concentration . In another variation of air-lift reactor, when calcium carbonate was confined to a cellulose membrane, calcium gluconate production was maximum (149 g/L) . At higher specific growth rate, obtained in shake flask, despite the formation of cell pellets, product formation was low . Physical separation of particulate calcium carbonate and growing cells favoured product formation . In stirred reactor pulpy mycelial growth was obtained and calcium gluconate production was poor. J Biol Chem, 1999 Oct 22, 274(43), 30794 - 8 Involvement of small GTPases in Mycoplasma fermentans membrane lipoproteins-mediated activation of macrophages; Rawadi G et al.; Mycoplasma fermentans lipoproteins (LAMPf) are capable of activating macrophages and inducing the secretion of proinflammatory cytokines . We have recently reported that mitogen-activated protein kinase (MAPK) pathways and NF-kappaB and activated protein 1 (AP-1) play a crucial role in the activation induced by this bacterial compound . To further elucidate the mechanisms by which LAMPf mediate the activation of macrophages, we assessed the effects of inhibiting small G proteins Rac, Cdc42, and Rho . The Rho-specific inhibitor C3 enzyme completely abolished the secretion of tumor necrosis factor alpha by macrophages stimulated with LAMPf and also inhibited the activation of extracellular signal-regulated kinase (ERK), c-Jun NH(2)-terminal kinase (JNK), and p38 kinase . In addition, we have shown that LAMPf stimulate Cdc42 and that inhibition of Cdc42 or Rac by dominant negative mutants abrogates LAMPf-mediated activation of JNK and transactivation of NF-kappaB and AP-1 in the murine macrophage cell line RAW 264.7 . These results indicate that small G proteins Rho, Cdc42, and Rac are involved in the cascade of events leading to the macrophage activation by mycoplasma lipoproteins. J Anim Sci, 1999 Oct, 77(10), 2817 - 23 Feeding value of wheat-based thin stillage: in vitro protein degradability and effects on ruminal fermentation; Iwanchysko P et al.; Two experiments were conducted to evaluate the nutritive value of wheat-based thin stillage as a fluid source for ruminants . In vitro CP degradability of thin stillage was estimated relative to canola meal and heated canola meal in a completely randomized design . Four ruminally cannulated steers were used in a double cross-over design to determine the effects of consuming thin stillage or water as drinking sources on ruminal fermentation traits . The in vitro CP degradability of thin stillage (55.4%) was lower (P<.05) than that of canola meal (59.4%) and higher than that of heated canola meal (31.6%) . Ruminal pH for steers consuming thin stillage was higher (P<.05) at 1000 and 1100 and lower (P<.05) at 1900 and 2000 than that for steers consuming water . Total VFA followed a pattern that was the reverse of that reported for pH . Ruminal NH3 N levels were higher (P<.05) for steers fed thin stillage than for water-fed steers through most of the collection period . Ruminal fluid and particulate matter passage rates were not affected by treatment and averaged .165 and .06 /h, respectively . The amount of thin stillage and water that did not equilibrate with the ruminal fluid and, thus, was considered to bypass the rumen was estimated to be 51.9 and 59.2% of total fluid consumed, respectively . Feeding wheat-based thin stillage had no adverse effects on ruminal metabolism. J Anim Sci, 1999 Oct, 77(10), 2793 - 802 Effects of different supplemental sugars and starch fed in combination with degradable intake protein on low-quality forage use by beef steers; Heldt JS et al.; Twenty ruminally fistulated steers (Exp . 1, 448 kg and Exp . 2, 450 kg) were used in two consecutive randomized complete block experiments with five treatments in each experiment . The purpose was to evaluate the impact of feeding different supplemental sugars or starch in combination with supplemental degradable intake protein (DIP) on the utilization of low-quality tallgrass-prairie hay . In Exp . 1, steers were given ad libitum access to forage and, except for the negative control (NC), received a limited supply (insufficient to maximize forage use) of supplemental DIP (.031% BW/d, DM basis) . In addition to the NC, this experiment included four supplementation treatments in which one of four carbohydrate (CHO) sources (starch, glucose, fructose, or sucrose) was fed at .30% BW of DM/d . In Exp . 2, the treatment structure was identical except that the supplemental DIP level (.122% BW, DM basis) was near the level needed to maximize forage use . Forage OM intake (FOMI) was not affected (P> or =.26) by supplementation in Exp . 1 but was increased (P = .05) in Exp . 2 . However, no difference (P> or =.46) in FOMI occurred among CHO sources in either experiment . Total OM and digestible OM intakes were increased (P<.01) by supplementation in both experiments . In Exp . 1, no difference (P>.26) in OM digestion (OMD) occurred among treatments . In Exp . 2, supplementation increased (P<.01) OMD . Additionally, sugars yielded a higher (P = .04) OMD than starch, and the monosaccharides yielded a higher (P = .02) OMD than sucrose . In Exp . 1, NDF digestion (NDFD) was decreased (P = .02) by supplementation, but no differences (P> or =.21) occurred among CHO sources . In Exp . 2, NDFD was increased (P = .03) by supplementation . Additionally, sugars led to higher (P = .05) NDFD than starch, and the monosaccharides led to higher (P = .03) NDFD than sucrose . In both experiments, discernible patterns were observable with regard to the effects of supplementation and type of supplemental CHO on ruminal fermentation characteristics . In conclusion, even though some consistency in fermentation profiles for different carbohydrate sources was evident in both experiments, forage intake and digestion responses were not consistent across experiments . This raises the possibility that carbohydrate source may interact with the amount of supplemental DIP fed and, as such, deserves additional investigation. J Anim Sci, 1999 Oct, 77(10), 2781 - 92 Influence of postruminal supplementation of methionine and lysine, isoleucine, or all three amino acids on intake and chewing behavior, ruminal fermentation, and milk and milk component production; Robinson PH et al.; Four multiparous Holstein cows were fed a basal diet balanced with the Cornell Net Protein and Carbohydrate System (CNCPS) . Diets were formulated to be co-limiting in intestinally absorbable supplies of methionine, lysine, and isoleucine . Cows were supplemented with no amino acids (control); lysine and methionine in a ruminally protected form; isoleucine by abomasal infusion; or lysine, methionine, and isoleucine in a 4x4 Latin square arrangement of treatments with 28-d periods . Performance of cows on all treatments was lower than expected due to low intake of DM that could have been caused by the high fiber level of the basal diet . This high fiber level was likely responsible for the high daily chewing times for cows fed all diets, which was consistent with the high ruminal pH values . Intake of DM and its components were not influenced by any treatment . Milk protein percentage tended to be higher when cows were fed diets supplemented with ruminally protected lysine and methionine; however, production of milk, milk fat, and milk lactose were not affected by any treatment . Cows tended to have a higher milk lactose proportion and tended to produce more milk and milk lactose when they were abomasally infused with isoleucine alone . However, when cows were supplemented with all three amino acids, milk production and composition did not differ from that of cows fed the unsupplemented diet . Use of the CNCPS to evaluate the performance of the cows fed the unsupplemented diet suggested that these cows may have been colimited by intestinally absorbable supplies of lysine, isoleucine, and methionine in addition to metabolizable protein . Evaluation of the unsupplemented diet with an alternate model, Shield, suggested that cows fed the unsupplemented diet may have been colimited by intestinally absorbable supplies of lysine, isoleucine, and arginine . Results suggest that enhanced delivery of intestinally absorbable isoleucine may stimulate milk lactose synthesis. J Anim Sci, 1999 Oct, 77(10), 2774 - 80 Low- and high-quality forage utilization by heifers and mature beef cows; Varel VH et al.; Eight cows (7 to 9 yr old, 522 kg) and six heifers (10 mo old, 169 kg) were fed either alfalfa hay (18.7% CP) or mature brome hay (5.1% CP) to determine the effect of cattle age on apparent forage utilization . Cattle were fitted with ruminal and duodenal cannulas and were individually fed once daily (ad libitum intake, 1000) . The split-plot design consisted of age (whole-plot) and two sampling periods feeding alfalfa or brome hay (subplot) . Each period consisted of 28 d: d 1 to 13 for adaptation, d 13 to 20 for feed intake determination, and d 20 to 28 for sampling . Nylon bags containing NDF substrate from alfalfa or brome hay were incubated ruminally for 0, 3, 6, 12, 24, 48, 96, and 192 h to determine the rate and extent of fiber degradation . Ruminal liquid dilution rate and fermentation characteristics were conducted on d 27 . Ruminal fill was determined by total evacuation at 0800 on d 28 . Cows consumed more feed (BW.75; P<.01) and had greater ruminal OM fill (P = .04) but had similar fluid fill (P = .88) compared with heifers . Ruminal liquid dilution rate was greater in cows than in heifers (P<.01) . The rate of in situ NDF degradation was 3 and .5% per hour greater in cows than in heifers when alfalfa and brome hay were fed, respectively (age x hay, P<.01) . Ruminal NDF digestibility as a percentage of intake was greater in cows than in heifers (P<.01) . Numbers of ruminal cellulolytic bacteria were not affected by treatment (P>.21) . These data indicate that mature cows have a smaller ruminal fluid fill that turns over more rapidly, and this may be responsible for a faster rate of ruminal fiber degradation in cows than in young heifers. J Anim Sci, 1999 Oct, 77(10), 2721 - 9 Changes in gastric contents in pigs fed a finely ground and pelleted or coarsely ground meal diet; Regina DC et al.; The objective was to characterize the change in stomach contents in relation to time after feeding between pigs consuming a restricted amount of a finely ground and pelleted (FGP) or coarsely ground meal (CGM) diet . Particular interest was placed on the concentration of organic acids and ammonia, the products of microbial fermentation . Thirty barrows were ranked by weight and assigned to a postfeeding time of 2, 4, 6, 8, or 12 h and either the FGP or CGM diet . Initiation and termination of the experiment were staggered over a 2-wk period . The treatment period was 42 d . Percentage of dry matter was higher (P<.01) in the stomach contents of pigs on the CGM diet . Concentrations of pepsin and protein were higher (P<.05) and ammonia tended to be higher (P = .10) in the proximal stomach of pigs fed the FGP diet . In contrast, concentrations of acetate and L-lactate were higher (P<.05) in the proximal stomach of pigs fed the CGM diet . All pigs on the CGM diet had stomachs that graded as normal on visual inspection . There was variable damage to the stomachs of pigs on the FGP diet . Measurement of chromium concentration in the stomach after an oral dose of Cr-EDTA clearly demonstrated the mixing that occurs between the proximal and distal stomach by 2 h after feeding in pigs consuming the FGP diet, whereas a gradient was maintained in pigs consuming the CGM diet . Thus, components normally secreted in the distal stomach return to the proximal stomach . These data show that components secreted in the distal region, such as acid and pepsin, may play a role in initiating damage to the stratified squamous mucosa . High concentrations of organic acids in the stomach of pigs on the CGM diet were not associated with damage to the stratified squamous mucosa in the esophageal region. Curr Med Chem, 1999 Dec, 6(12), 1197 - 212 Chemistry and structure activity relationships of bafilomycin A1, a potent and selective inhibitor of the vacuolar H+-ATPase; Gagliardi S et al.; Bafilomycin A1, a macrolide antibiotic isolated from the fermentation of Streptomyces spp., is a potent and selective inhibitor of vacuolar-type proton translocating ATP-ases (V-ATPases) and was used to study the physiological role of this class of enzymes . An extensive chemical effort on the unusual structure of this macrolide led to the synthesis of significantly different bafilomycin derivatives . None of the new analogues was more potent than the parent compound but provided a significant amount of information about the structural requirements for the inhibitory activity of bafilomycin A1 in particular on chicken osteoclast (cOc) ATPase . The vinylic methoxy group adjacent to a carbonyl function, the dienic system and the hydroxy group at position 7 were recognized to be essential features for bafilomycin V-ATPase-inhibitory activity . This information was utilized to design simplified novel derivatives as inhibitors of bone resorption. Microbiology, 1999 Sep, 145 ( Pt 9), 2569 - 76 Oxalic acid production by Aspergillus niger: an oxalate-non-producing mutant produces citric acid at pH 5 and in the presence of manganese; Ruijter GJ et al.; The external pH appeared to be the main factor governing oxalic acid production by Aspergillus niger . A glucose-oxidase-negative mutant produced substantial amounts of oxalic acid as long as the pH of the culture was 3 or higher . When pH was decreased below 2, no oxalic acid was formed . The activity of oxaloacetate acetylhydrolase (OAH), the enzyme believed to be responsible for oxalate formation in A . niger, correlated with oxalate production . OAH was purified from A . niger and characterized . OAH cleaves oxaloacetate to oxalate and acetate, but A . niger never accumulated any acetate in the culture broth . Since an A . niger acuA mutant, which lacks acetyl-CoA synthase, did produce some acetate, wild-type A . niger is apparently able to catabolize acetate sufficiently fast to prevent its production . An A . niger mutant, prtF28, previously isolated in a screen for strains deficient in extracellular protease expression, was shown here to be oxalate non-producing . The prtF28 mutant lacked OAH, implying that OAH is the only enzyme involved in oxalate production in A . niger . In a traditional citric acid fermentation low pH and absence of Mn2+ are prerequisites . Remarkably, a strain lacking both glucose oxidase (goxC) and OAH (prtF) produced citric acid from sugar substrates in a regular synthetic medium at pH 5 and under these conditions production was completely insensitive to Mn2+. Int J Biol Macromol, 1999 Nov, 26(2-3), 201 - 11 Characterization by mass spectrometry of poly(3-hydroxyalkanoates) produced by Rhodospirillum rubrum from 3-hydroxyacids; Ballistreri A et al.; The sequence distributions of two microbial copolyesters obtained by fermentation of Rhodospirillum rubrum, grown with 3-hydroxyhexanoic or 3-hydroxyheptanoic acids, were determined by analyzing the oligomers prepared by partial pyrolysis or partial methanolysis of these copolyesters using fast atom bombardment mass spectrometry (FAB-MS) . Oligomers up to pentamers were identified in the case of partial pyrolysis and up to tetradecamers in the case of partial methanolysis . The comparison between the experimental and calculated peak intensities of FAB mass spectra allows the calculation of compositions and sequence distributions, which in these copolyesters follow Bernoullian statistics, indicating that they are random terpolyesters. Plant Foods Hum Nutr, 1999, 53(3), 199 - 208 Studies on the production of bambara groundnut (Vigna subterranea) tempe; Amadi EN et al.; Bambara groundnut, an indigenous African legume, was subjected to fermentation by three strains of Rhizopus . One strain B . arrhizus could not ferment the substrate . Mycelial penetration and binding was good when strains NRRL 2710 (R . oligosporus) and NRRL 1477 (R . stolonifer) were used . Fermentation by both strains resulted in increases of pH, moisture, protein and fat while total carbohydrate decreased by 50% . Sensory evaluation showed that bambara groundnut tempes rated similar (p>0.5) in taste and texture and higher (p<0.05) in color and flavor than soybean tempe . Bambara groundnut would be an acceptable food product in the diet as a good protein supplement. Biotechnol Bioeng, 1999 Dec 5, 65(5), 550 - 7 Visualizing integrated bioprocess designs through "windows of operation"; Zhou YH et al.; This paper demonstrates a simple graphical approach for the design and analysis of a bioprocess flowsheet in which process interactions are significant . Results are presented showing how the feasible space for operation can be simulated and used both to address key design and operating decisions and to identify suitable trade-offs between operating variables, such as fermentation growth rate and disruption conditions, in order to achieve prespecified levels of process performance . Using verified models to describe the production and isolation of an intracellular protein alcohol dehydrogenase (ADH) in yeast as a test bed, a series of so-called "windows of operation" are developed at growth rates in the range of 0.06-0.28 h(-1) and for a range of overall process specifications . The effects of altering the process design performance specification as defined by the level of cell debris removal and the overall process productivity on the size and position of the feasible space were investigated to demonstrate the sensitivity of the flowsheet to changes in process objectives . Using the approach it has been possible to visualise the processing trade-offs required to increase performance in terms of the level of cell debris removal by 50% and the overall process productivity by 400% from a defined base level . The approach provides a convenient tool when designing integrated bioprocesses by enabling process options to be compared visually and can help in achieving better process designs and accelerating process development for the biological process industry . Biotechnol Bioeng, 1999 Dec 5, 65(5), 537 - 41 Dielectric analysis for estimation of oil content in the mycelia of Mortierella alpina; Higashiyama K et al.; The dielectric behavior of the filamentous fungi Mortierella alpina SAM2104 and 1S-4, which produce polyunsaturated fatty acid enriched oil in the mycelia, was investigated . During the cultivation carried out in a 10-kL fermentor for 12-15 days, the relative permittivity and conductivity of the broth were measured in the frequency range of 100 kHz to 30 MHz . The dielectric parameters, i.e., the amplitude of dielectric relaxation (Deltaepsilon) and the characteristic frequency (f(c)), were obtained by fitting the Cole-Cole equation to the observed dielectric relaxation, and the conductivity of the medium (kappa(a)) was also measured . The value of Deltaepsilon gradually increased from the second day through the end of cultivation, suggesting that volume fraction of the cell increased with oil accumulation . The conductivity of the cytoplasm (kappa(i)) was calculated from the experimental values of f(c) and kappa(a), using a theoretical equation based on an ellipsoidal cell model . As a result, good correlation between the calculated kappa(i) and the oil content was obtained . These findings indicate that dielectric analysis enables us to estimate the oil content in the mycelia of oleaginous fungi and also provides a useful tool for monitoring cell growth and for controlling the cultivation process . Biotechnol Bioeng, 1999 Dec 5, 65(5), 512 - 22 Macroscopic growth of filamentous fungi on solid substrate explained by a microscopic approach; Ferret E et al.; A quantitative model predicting biomass growth on solid media has been developed . The model takes into account steric interactions between hyphae and tips at the microscopic level (competition for substrate and tip-hypha collisions) . These interactions effect a slowing down of the hyphal, population-averaged extension rate and are responsible, at the microscopic level, for the distribution of tip orientations observed at the colony border . At the macroscopic level, a limiting value of the colony radial extension rate is attained . A mathematical model that combines hyphal branching, tip diffusion, and biomass growth was proposed to explain such behavior . Experiments using Gibberella fujikuroi were performed to validate the model; good agreement between experiments and simulations was achieved . Most parameters can be measured by simple image analysis on the peripheral growth zone, and they have clear physical meaning; that is, they correspond to properties of single, leading hyphae . The model can be used to describe two-dimensional (2D) solid media fermentation experiments under varying culture conditions; the model can also be extended to consider growth in three-dimensional (3D), complex geometry substrates . Biotechnol Bioeng, 1999 Dec 5, 65(5), 500 - 11 Influence of fermentation conditions and microfiltration processes on membrane fouling during recovery of glucuronane polysaccharides from fermentation broths; Harscoat C et al.; We have investigated the recovery of exopolysaccharides produced by Sinorhizobium meliloti M5N1 CS bacteria from fermentation broths using different membrane filtration processes: cross-flow filtration with a 7 mm i.d . tubular ceramic membrane of 0.5-microm pores under fixed transmembrane pressure or fixed permeate flux and dynamic filtration with a 0.2 microm nylon membrane using a 16-cm rotating disc filter . With the tubular membrane, the polysaccharide mass flux was mainly limited by polymer transmission that decayed to 10% after 90 min . The mass flux of polymer produced under standard fermentation conditions (70 h at 30 degrees C) stabilized after 70 min to 15 g/h/m(2) . This mass flux rises to 36 g/h/m(2) when the mean stirring speed during fermentation is increased and to 123 g/h/m(2) when fermentation is extended to 120 h . In both cases, the mean molecular weight of polysaccharides drops from 4.0 10(5) g/mol under standard conditions to 2.7 10(5) g/mol . A similar reduction in molecular weight was observed when the fermentation temperature was raised to 36 degrees C without benefit to the mass flux . These changes in fermentation conditions have little effect on stabilized permeate flux, but raise significantly the sieving coefficient, due probably to molecular weight reduction and the filamentous aspect of the polymer as observed from SEM photographs . The polymer-mass flux was also increased by reducing transmembrane pressure (TMP) and raising the shear rate by inserting a rod in the membrane lumen . Operation under fixed permeate flux instead of constant TMP inhibited fouling during the first 4 h, resulting in higher sieving coefficients and polymer mass fluxes . The most interesting results were obtained with dynamic filtration because it allows operation at high-shear rates and low TMP . Sieving coefficients remained between 90 and 100% . With a smooth disc, the polysaccharide mass flux remained close to 180 g/h/m(2) at 1500 rpm and cell concentrations from 1 to 3 g/L . When radial rods were glued to the disc to increase wall shear stress and turbulence, the mass flux rose to 275 g/h/m(2) at the same speed and cell concentration . Yeast, 1999 Oct, 15(14), 1555 - 64 Lipid composition of subcellular membranes of an FY1679-derived haploid yeast wild-type strain grown on different carbon sources; Tuller G et al.; The aim of the project EUROFAN (European Functional Analysis Network) is to elucidate the function of unknown genes of the yeast Saccharomyces cerevisiae at a large scale . Functional analysis is based on general and specific tests with yeast deletion strains . A prerequisite for these studies is a profound knowledge of the biochemistry and cell biology of the corresponding wild-type strain FY1679 . As a contribution from our laboratory we present here a systematic lipid analysis of the major organelles isolated from FY1679 grown in the presence of different carbon sources . Phospholipid, sterol and fatty acid composition are characteristic for each organelle . Moreover, growth of the yeast on glucose, ethanol or lactate causes in some cases marked changes of the organelle lipid pattern . As the most prominent example, cultivation of the yeast on non-fermentable carbon sources results in an increase of mitochondrial cardiolipin . As another example, the ratio of unsaturated to saturated fatty acids is enhanced in cells grown on ethanol or lactate as compared to glucose . Thus, the lipid composition of yeast subcellular membranes reflects in a significant way the nutrient conditions caused by variation of the carbon source . Biotechnol Prog, 1999 Oct 1, 15(5), 949 - 952 Simultaneous Optimization of Feeding Rate and Operation Parameters for Fed-Batch Fermentation Processes; Wang FS et al.; An efficient method is introduced for simultaneously determining optimal polices of feeding rate and operation parameters for a fermentation process . Such an optimization problem is converted into the finite dimensional optimization problem using the control parametrization technique . The hybrid differential evolution is introduced to solve the converted problem . The optimal production rate obtained by the simultaneous optimization approach could be significantly improved with comparison to a simplified optimization problem, which is considered the optimal feed control only, as observed from the simulation results. Biotechnol Prog, 1999 Oct 1, 15(5), 923 - 927 Estimation of O(2) and CO(2) Solubility in Microbial Culture Media; Gros JB et al.; A simple model for predicting gas solubilities of O(2) and CO(2) at low pressure and near ambient temperature in solutions of salts, sugars, and organic solvents (alcohols, ketones, ethers, aldehydes, etc.) is proposed . It is derived from the Van Laar assumptions and takes account of size differences between molecules in solution by their volumetric fraction . It is a group contribution model where anions and cations are considered as groups and other molecules are treated as in the UNIFAC (UNIQUAC Functional group Activity Coefficients) procedure . Pseudo-Henry's constants for groups were determined using solubility data in aqueous solutions containing only one salt, one sugar, or one organic compound at 25 degrees C . The predictive performance of the model was evaluated by comparison with experimental data using multicomponent aqueous salt-sugar mixtures . The model was used to estimate solubilities of oxygen and carbon