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Showing papers on "Growth medium published in 2001"


Journal ArticleDOI
TL;DR: Investigation of the basis for acetate-induced acid tolerance in E. coli O157:H7 found induction of RpoS expression did not appear to be sufficient to activate the acid tolerance response, and treatment with acetate increased acid survival.
Abstract: The ability of Escherichia coli to survive at low pH is strongly affected by environmental factors, such as composition of the growth medium and growth phase. Exposure to short-chain fatty acids, such as acetate, proprionate, and butyrate, at neutral or nearly neutral pH has also been shown to increase acid survival of E. coli and Salmonella enterica serovar Typhimurium. To investigate the basis for acetate-induced acid tolerance in E. coli O157:H7, genes whose expression was altered by exposure to acetate were identified using gene arrays. The expression of 60 genes was reduced by at least twofold; of these, 48 encode components of the transcription-translation machinery. Expression of 26 genes increased twofold or greater following treatment with acetate. This included six genes whose products are known to be important for survival at low pH. Five of these genes, as well as six other acetate-induced genes, are members of the E. coli RpoS regulon. RpoS, the stress sigma factor, is known to be required for acid tolerance induced by growth at nonlethal low pH or by entry into stationary phase. Disruption of the rpoS gene by a transposon insertion mutation also prevented acetate-induced acid tolerance. However, induction of RpoS expression did not appear to be sufficient to activate the acid tolerance response. Treatment with either NaCl or sodium acetate (pH 7.0) increased expression of an rpoS::lacZ fusion protein, but only treatment with acetate increased acid survival.

233 citations


Journal ArticleDOI
TL;DR: The results show that in addition to having an effect on the sorption characteristics of the growth media, soil micro-organisms also provided a source ofphytase for the dephosphorylation of phytate for subsequent utilization of Pi by plants.
Abstract: A range of pasture grass (Danthonia richardsonii and Phalaris aquatica) and legume (Medicago polymorpha, M. sativa, Trifolium repens and T. subterraneum) species showed limited capacity to obtain phosphorus (P) from inositol hexaphosphate (IHP), when grown in either sterile agar (pH 5.0 or 5.5) or sand-vermiculite media (pH 5.0). The total P content of shoots from IHP-supplied plants grown in agar was between 20% and 34% of that for seedlings supplied with an equivalent amount of P as inorganic phosphate (Pi), while in sand-vermiculite, the total P content of IHP-grown plants was between 5 and 10% of control plants. The poor ability of plants to utilize P from IHP resulted in significantly lower tissue P concentrations and, in general, reduced plant dry weight accumulation. In contrast, the P nutrition of plants supplied with IHP was significantly improved by inoculating media with either a cultured population of total soil micro-organisms or with a specific isolate of Pseudomonas sp., selected for its ability to release phosphate from IHP (strain CCAR59; Richardson and Hadobas, 1997 Can. J. Micro. 43, 509-516). In agar and sand-vermiculite media, respectively, the P content of IHP-grown plants increased with inoculation by up to 3.9- and 6.8-fold, such that the dry weight and P content of the plant material were equivalent to those observed for control plants supplied with Pi. However, the response to inoculation was dependent on the growth medium and the source of micro-organisms used. In sand-vermiculite, the cultured population of soil micro-organisms was effective when IHP was supplied at an equivalent level of Pi required for maximum plant growth. By comparison, inoculation of plants with the Pseudomonas strain was only effective at very high levels of IHP supply (×36), whereas in agar a response to inoculation occurred at all levels of IHP. The ability of pasture plants to acquire P from phytate was, therefore, influenced by the availability of IHP substrate, which was further affected by the presence of soil micro-organisms. Our results show that in addition to having an effect on the sorption characteristics of the growth media, soil micro-organisms also provided a source of phytase for the dephosphorylation of phytate for subsequent utilization of Pi by plants.

218 citations


Journal ArticleDOI
01 Sep 2001-Toxicon
TL;DR: Microcystin was detected in the tissues of exposed plants using a commercially available ELISA kit, suggesting that the uptake of these toxins by edible plants may have significant implications for human health.

191 citations


Journal ArticleDOI
TL;DR: The presence of L-cysteine in the medium was useful for induction of cell growth and the presence of ferrous sulfate and ferric gallate dramatically enhanced BMP yield as compared with ferric quinate, an iron chelate conventionally used.

150 citations


Journal ArticleDOI
TL;DR: The present work aimed to define a minimal chemically‐defined medium which could sustain the growth of most (if not all) strains of Streptococcus thermophilus.
Abstract: Aims: The present work aimed to define a minimal chemically-defined medium which could sustain the growth of most (if not all) strains of Streptococcus thermophilus. Methods and Results: A minimal medium containing 20 components, including one carbohydrate source, six amino acids, two metallic ions, six vitamins and urea allowed for growth of 13 out of 15 Strep. thermophilus strains. Growth of the two last strains required the presence of additional amino acids, the number of which depended on the strain. Growth rates of the strains in the minimal medium ranged from 0·38 to 0·64 h–1, and final populations were about 108 cfu ml–1. Conclusions: Streptococcus thermophilus appears much less demanding than other lactic acid bacteria. Significance and Impact of the Study: The definition of such a growth medium will be very useful for metabolic flux studies as well as peptide transport studies.

142 citations


Journal ArticleDOI
TL;DR: Results suggest that SOD may have a role in the defensive mechanisms against high concentrations of CuSO4 in strain N6, a yeast strain isolated from deep-sea sediment samples collected at a depth of 4500 m to 6500 m in the Japan Trench.
Abstract: Thirteen yeast strains were isolated from deep-sea sediment samples collected at a depth of 4500 m to 6500 m in the Japan Trench. Amongst them, strain N6 possessed high tolerance against Cu2+ and could grow on yeast extract/peptone/dextrose/agar containing 50 mM CuSO4. Analysis of the 18S rDNA sequence indicates strain N6 belongs to the genus Cryptococcus. In contrast, the type strain of C. albidus, a typical marine yeast Rhodotorula ingeniosa and Saccharomyces cerevisiae did not grow at high concentrations of CuSO4. Superoxide dismutase (SOD) catalyzes the scavenging of superoxide radicals. The activity of SOD in cell extract of strain N6 was very weak (<1 mU μg−1 total protein) when the strain was grown in the absence of CuSO4. However, the activity was stimulated (25.8 mU μg−1 total protein) when cells were grown with 1 mM CuSO4 and further enhanced to 110 mU μg−1 total protein with 10 mM CuSO4. Catalase activity was increased only 1.4 or 1.1-fold with 1 mM or 10 mM CuSO4 in the growth medium, respectively. These results suggest that SOD may have a role in the defensive mechanisms against high concentrations of CuSO4 in strain N6.

82 citations


Journal ArticleDOI
TL;DR: In addition to carbon limitation at low, and nitrogen limitation at high C()/N() ratios, an intermediate growth regime of simultaneous limitation by carbon and nitrogen was detected where both substrates were used to completion.
Abstract: Pseudomonas oleovorans (ATCC 29347) was grown in batch and chemostat cultures with citrate, hexanoate, heptanoate, octanoate, and nonanoate as single carbon substrates. The growth medium for batch cultures was adjusted such that nitrogen (NH4+) limitation terminated the exponential-growth phase. During batch cultivation with octanoate or nonanoate the biomass continued to increase after depletion of ammonium due to the accumulation of medium-chain-length poly[(R)-3-hydroxyalkanoates] (mcl-PHAs). Additionally, a significant rate of mcl-PHA accumulation was also observed in the exponential-growth phase of batch cultures. It is well known that the accumulation of reserve materials is strongly dependent on the ratio of nutrients (here of carbon, C, and of nitrogen, N) and that in a batch culture the ratio of C:N is continuously changing. Therefore, we have also investigated the effect of defined ratios of C:N under constant cultivation conditions, namely at a fixed dilution rate (D) in a chemostat fed with different medium C:N ratios. These experiments were performed at a constant D of 0.2 h−1. The concentration of the nitrogen source in the inflowing medium (N) was kept constant, while its carbon concentration (C) was increased stepwise, resulting in an increase of the medium carbon to nitrogen ratio (C/N ratio). The culture parameters and the cell composition of steady-state cultures were determined as a function of the C/N ratio in the feed medium. Mcl-PHA accumulation was detected during growth with the fatty acids, and three distinct regimes of growth limitation were discovered: In addition to carbon limitation at low, and nitrogen limitation at high C/N ratios, an intermediate growth regime of simultaneous limitation by carbon and nitrogen was detected where both substrates were used to completion. The width of this dual-nutrient-limited growth regime was dependent on the change in the yield factors for carbon and nitrogen (YX/C, YX/N) measured during single-nutrient-limited growth. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 72: 278–288, 2001.

80 citations


Journal ArticleDOI
TL;DR: Xylitol is the only commercially used sugar substitute proven to have an antimicrobial effect on pneumococci, and this finding implies that xylitol-induced inhibition of pneumococcal growth is mediated via the fructose phosphotransferase system in a way similar to that in which mutans group streptococcalgrowth is inhibited.
Abstract: Xylitol is effective in preventing acute otitis media by inhibiting the growth of Streptococcus pneumoniae. To clarify this inhibition we used fructose, which is known to block similar growth inhibition observed in Streptococcus mutans. In addition, we evaluated the efficacy of sorbitol in inhibiting the growth of pneumococci, as sorbitol is widely used for indications similar to those for which xylitol is used. The addition of 5% xylitol to the growth medium resulted in marked growth inhibition, an effect which was totally eliminated in the presence of 1, 2.5, or 5% fructose but not in the presence of 1 or 5% glucose, 1% galactose, or 1% sucrose. This finding implies that xylitol-induced inhibition of pneumococcal growth is mediated via the fructose phosphotransferase system in a way similar to that in which mutans group streptococcal growth is inhibited. The addition of sorbitol at concentrations of 1, 2.5, or 5% to the growth medium did not affect the growth of pneumococci and neither inhibited nor enhanced the xylitol-induced growth impairment. Thus, it seems that xylitol is the only commercially used sugar substitute proven to have an antimicrobial effect on pneumococci.

53 citations


Patent
09 May 2001
TL;DR: A chemically defined-serum free growth medium for the in vitro and ex vivo of cells and cell lines is described in this article, which consists of about a one to one ratio (v/v) of two basal growth media containing α-ketoglutarate, insulin, transferrin, selenium, bovine serum albumin, linoleic acid, ceruloplasmin, cholesterol, phosphatidyl-ethanolamine, α-tocopherol acid succinate, reduced glutathione, taurine, triiodothyronine
Abstract: A chemically defined-serum free growth medium for the in vitro and ex vivo of cells and cell lines. The medium consists of about a one to one ratio (v/v) of two basal growth media containing α-ketoglutarate, insulin, transferrin, selenium, bovine serum albumin, linoleic acid, ceruloplasmin, cholesterol, phosphatidyl-ethanolamine, α-tocopherol acid succinate, reduced glutathione, taurine, triiodothyronine, hydrocortisone, parathyroid hormone, L-ascorbic acid 2-sulfate, β-glycerophosphate, PDGF, EGF and FGF. Chondrocytes, when cultured in this medium in the presence of a cartilage derived morphogenetic protein or bone morphogenetic protein, retain their cartilaginous phenotype.

46 citations


Journal ArticleDOI
TL;DR: Phospholipase production by various isolates of Pseudomonas was investigated and pasteurization reduced the activity, but did not eliminate it in skim milk.
Abstract: Many psychrotrophic bacteria contaminating raw milk produce phospholipase that withstands pasteurization and UHT treatments. This enzyme acts on the milk fat globule membrane and exposes triacylglycerides to the action of lipase. Phospholipase production by various isolates of Pseudomonas was investigated. The isolates were cultured aerobically at 8 °C in nutrient broth, McKellar's minimal salts medium, Chrisope's medium, and skim milk. Each strain produced phospholipase during the 50 h incubation. Enzyme production varied significantly (P < 0·001) with strain and growth medium. Strains varied significantly (P < 0·001) in their enzyme production in each medium and during the incubation time as well. Strain, incubation time, and the growth medium significantly influenced (P < 0·001) heat stability of the enzyme activity. Pasteurization reduced the activity, but did not eliminate it in skim milk.

42 citations


Journal ArticleDOI
TL;DR: The aim of this study was to improve CTAS agar by broadening its spectrum of selective recovery for carnobacteria while restricting the ability of interfering species to grow.

Journal ArticleDOI
TL;DR: A novel single-step microbial transformation process for the production of testosterone from cholestrol by Lactobacillus bulgaricus in an aerated fermenter with significant increase in the presence of cyclodextrin in the fermenting medium was investigated.

Journal ArticleDOI
TL;DR: The optimum conditions for the intracellular synthesis of the cyclic amino acid ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyridine carboxylic acid) were determined using the halotolerant Brevibacterium sp. JCM 6894 as mentioned in this paper.

Journal ArticleDOI
TL;DR: Bacillus subtilis BD170, harboring a plasmid pGT44[phyC] carrying the phytase gene (phyC) and a phosphate-depletion inducible pst-promoter, was grown in a 2 l bioreactor and high cell densities were achieved with peptone and yeast extract as the complex nitrogen sources in a semi-defined growth medium.
Abstract: Bacillus subtilis BD170, harboring a plasmid pGT44[phyC] carrying the phytase gene (phyC) and a phosphate-depletion inducible pst-promoter, was grown in a 2 l bioreactor. Using a controlled feeding of glucose, high cell densities of 32 and 56 g dry cell weight l−1 were achieved with peptone and yeast extract, respectively, as the complex nitrogen sources in a semi-defined growth medium. The fed-batch protocol was applied to production of recombinant phytase and a high extracellular phytase activity (48 U ml−1) was reached with peptone. Although the yeast extract feeding resulted in a higher cell density, it was unsuitable as a medium component for phytase expression due to its relatively high phosphate content.

Journal ArticleDOI
TL;DR: Cell death was inhibited by the addition of Actinomycin D or through modifications of the culture conditions either by reducing the oxygen tension or by decreasing the temperature of the growth medium, and plastic caps in well‐filled vials release substances, which promote cell survival.

Journal ArticleDOI
TL;DR: It is concluded that the 29‐nucleotide 3′‐UTR element is an mRNA destabilizer whose function can be inhibited by inclusion of the aforementioned mixture of growth factors in the culture medium.
Abstract: Using a cell-free translation system, we previously demonstrated that the turnover and translation of amyloid precursor protein (APP) mRNA was regulated by a 29-nucleotide instability element, located 200 nucleotides downstream from the stop codon. Here we have examined the regulatory role of this element in primary human capillary endothelial cells under different nutritional conditions. Optimal proliferation required a growth medium (endothelial cell growth medium) supplemented with epidermal, basic fibroblast, insulin-like, and vascular endothelial growth factors. In vitro transcribed mRNAs with the 5'-untranslated region (UTR) and coding region of beta-globin and the entire 3'-UTR of APP 751 were transfected into cells cultured in endothelial cell growth medium. Wild-type globin-APP mRNA containing an intact APP 3'-UTR and mutant globin-APP mRNA containing a mutated 29-nucleotide element decayed with identical half-lives (t 1/2 = 60 min). Removal of all supplemental growth factors from the culture medium significantly accelerated the decay of transfected wild-type mRNA (t 1/2 = 10 min), but caused only a moderate decrease in the half-life of transfected mutant mRNA (t 1/2 = 40 min). We therefore conclude that the 29-nucleotide 3'-UTR element is an mRNA destabilizer whose function can be inhibited by inclusion of the aforementioned mixture of growth factors in the culture medium.

Journal Article
TL;DR: Results indicate that cells of Synechococcus sp.
Abstract: Synechococcus sp. PCC 7002 cells appeared to be nitrogen limited when grown on urea without nickel in the growth medium; the amounts of chlorophyll a and phycobiliproteins decreased and glycogen accumulated to high levels. When nickel was added to the urea medium, the diagnostics of nitrogen limitation was not observed. The activity of urease was dependent on the presence of nickel no matter what nitrogen source was used for cell growth. The ureC gene encoding the α-subunit of urease was constitutively transcribed in cells grown on all nitrogen sources tested. The addition of nickel to the growth medium rapidly led to a 15-fold increase in urease activity in 2 hours. These results indicate that cells of Synechococcus sp. PCC 7002 require a nickel supplement (5 μM NiSO4 in the growth medium) to utilize urea efficiently, and that Synechococcus sp. PCC 7002 cells are nickel-starved under the laboratory conditions regularly used for this strain. In two fresh water strains of cyanobacteria, Synechocystis sp. PCC 6803 and Anabaena sp. PCC 7120, high levels of urease activity were detected without addition of nickel to the growth medium, suggesting that these fresh water strains have a high-affinity uptake system for nickel or that their nickel requirements are lower than Synechococcus sp. PCC 7002.

Journal ArticleDOI
TL;DR: In this paper, the presence of nickel in the growth medium of Synechococcus sp. PCC 7002 cells was found to increase urease activity in 2 hours.
Abstract: Synechococcus sp. PCC 7002 cells appeared to be nitrogen limited when grown on urea without nickel in the growth medium; the amounts of chlorophyll a and phycobiliproteins decreased and glycogen accumulated to high levels. When nickel was added to the urea medium, the diagnostics of nitrogen limitation was not observed. The activity of urease was dependent on the presence of nickel no matter what nitrogen source was used for cell growth. The ureC gene encoding the α-subunit of urease was constitutively transcribed in cells grown on all nitrogen sources tested. The addition of nickel to the growth medium rapidly led to a 15-fold increase in urease activity in 2 hours. These results indicate that cells of Synechococcus sp. PCC 7002 require a nickel supplement (5 μM NiSO4 in the growth medium) to utilize urea efficiently, and that Synechococcus sp. PCC 7002 cells are nickel-starved under the laboratory conditions regularly used for this strain. In two fresh water strains of cyanobacteria, Synechocystis sp. PCC 6803 and Anabaena sp. PCC 7120, high levels of urease activity were detected without addition of nickel to the growth medium, suggesting that these fresh water strains have a high-affinity uptake system for nickel or that their nickel requirements are lower than Synechococcus sp. PCC 7002.

Journal ArticleDOI
TL;DR: The results suggest that the growth medium of S. anulatus has a fundamental role in the ability of the spores to induce inflammatory responses and cytotoxicity in mammalian cells.
Abstract: Epidemiological studies have shown an association between microbial growth in buildings and increased risk of respiratory symptoms and disease related to inflammatory reactions in the inhabitants96. The current study examined the affects of growth conditions of Streptomyces anulatus, isolated from indoor air of a moldy building, on the inflammatory potential of spores of this microbe. Spores were harvested from 15 growth media formulations, applied to RAW264.7 macrophages (10(5), 10(6), or 10(7) spores/million cells), and evaluated for the ability to stimulate production of inflammatory mediators and cytotoxicity in these cells 24 h after exposure. Streptomyces anulatus spores induced dose-dependent production of nitric oxide (NO) in macrophages, reaching a level from 4.2 microM to 39.2 microM depending on the composition of the growth medium of the microbe. Expression of inducible NO synthase (iNOS) was detected in macrophages after exposure to spores collected from all growth media. Production of reactive oxygen species (ROS) was significantly increased only by the highest dose of S. anulatus spores grown on glycerol-arginine agar. Furthermore production of cytokines was affected by growth medium; the highest dose-dependent levels of interleukin 6 (IL-6) ranged from 900 to 7800 pg/ml, and the levels of tumor necrosis factor alpha (TNFalpha) varied from 490 to 3200 pg/ml. The amount of dead macrophages after the exposure varied from 11% to 96%, depending also on the growth media of the microbe. Altogether, our results suggest that the growth medium of S. anulatus has a fundamental role in the ability of the spores to induce inflammatory responses and cytotoxicity in mammalian cells.

Journal ArticleDOI
TL;DR: While the wild type of tannic acid resistant mutants was very sensitive to iron deprivation conditions when grown in aerobic conditions, the mutants, whether grown aerobically or anaerobically, showed the same growth rate under iron-limited conditions as underIron-repleted conditions.
Abstract: Tannic acid inhibited the growth of the yeast Saccharomyces cerevisiae. Growth medium supplementation with more nitrogen or metal ions showed that only iron ions could restore the maximal growth rate of S. cerevisiae. Tannic acid resistant mutants were previously isolated by screening for tannic acid resistance and were all cytoplasmic petite mutants. While the wild type was very sensitive to iron deprivation conditions when grown in aerobic conditions, the mutants, whether grown aerobically or anaerobically, showed the same growth rate under iron-limited conditions as under iron-repleted conditions. Also, the wild type grown anaerobically was not affected by iron-limited conditions. Cytoplasmic petite mutants obtained by ethidium bromide mutagenesis behaved like the other mutants. During iron limitation, the wild type showed a reduced oxygen uptake rate. Maximal growth rate of the wild type in iron-limited conditions could be restored by the addition to the media of unsaturated fatty acids and sterol. Iron deprivation caused by tannic acid may thus affect the synthesis of a functional respiratory chain as well as the synthesis of unsaturated fatty acids and (or) sterol.

Journal ArticleDOI
TL;DR: The ability of Agrobacterium tumefaciens RU-OR cells to produce active enzymes was found to be dependent upon the choice of nitrogen source and the presence of inducer, 2-thiouracil, in the growth medium, which offered the potential for native enzyme production levels equivalent to those achieved by current heterologous expression systems.
Abstract: While the hydantoin-hydrolysing enzymes from Agrobacterium strains are used as biocatalysts in the commercial production of D-p-hydroxyphenylglycine, they are now mostly produced in heterologous hosts such as Escherichia coli. This is due to the fact that the activity of these enzymes in the native strains is tightly regulated by growth conditions. Hydantoinase and N-carbamoylamino acid amidohydrolase (NCAAH) activities are induced when cells are grown in the presence of hydantoin or an hydantoin analogue, and in complete medium, enzyme activity can be detected only in early stationary growth phase. In this study, the ability of Agrobacterium tumefaciens RU-OR cells to produce active enzymes was found to be dependent upon the choice of nitrogen source and the presence of inducer, 2-thiouracil, in the growth medium. Growth with (NH4)2SO4 as the nitrogen source repressed the production of both enzymes (nitrogen repression) and also resulted in a rapid, but reversible loss of hydantoinase activity in induced cells (ammonia shock). Mutant strains with inducer-independent production of the enzymes and/or altered response to nitrogen control were isolated. Of greatest importance for industrial application was strain RU-ORPN1F9, in which hydantoinase and NCAAH enzyme activity was inducer-independent and no longer sensitive to nitrogen repression or ammonia shock. Such mutants offer the potential for native enzyme production levels equivalent to those achieved by current heterologous expression systems.

Journal ArticleDOI
TL;DR: The results suggest that ALT301 cells have an internal tolerance mechanism, which makes cells grow normally in spite of Al accumulation and Al-induced lesion represented by the deposition of callose, which seems also to be effective against copper and iron toxicity.
Abstract: Aluminum (Al)-tolerant cell lines (ALT301 and ALT401) of tobacco were isolated in a simple calcium (Ca) solution from ethyl methane sulfonate (EMS)-treated suspension cultured tobacco cells (Nicotiana tabacum L. cv. Samsun, a cell line SL) at the logarithmic phase of growth. A highly tolerant cell line ALT301 exhibited the accumulation of Al and the deposition of callose to the same extent as the parental SL cells during the exposure to Al. However, the Al-treated ALT301 cells grew much better than the Al-treated SL cells after transfer to Al-free growth medium. Compared to SL cells, ALT301 cells were more tolerant to toxicity of copper and iron, but not to that of lanthanum. These results suggest that ALT301 cells have an internal tolerance mechanism, which makes cells grow normally in spite of Al accumulation and Al-induced lesion represented by the deposition of callose. This tolerance mechanism seems also to be effective against copper and iron toxicity. A slightly tolerant cell line ALT401 also accumulated Al to the same degree as SL cells, but deposited significantly less callose than did SL cells (43% of SL). The growth of ALT401 cells after Al treatment was only slightly better than that of SL cells. Thus, it seems that ALT401 cells have a mechanism to protect cells only from the Al-induced deposition of callose, which is not enough to overcome the Al-induced inhibition of growth. The different phenotypes exhibited by these Al-tolerant cell lines suggest that the deposition of callose is not directly related to the inhibition of growth in Al-treated cells.

Journal ArticleDOI
TL;DR: Comparison of whole-cell lysates of the strains tested in PAAG-SDS showed that, in addition to previously described Yops, Y. pestis synthesised new acidic proteins which appeared only under acidic conditions and were encoded by pLCR or chromosomally.
Abstract: Growth medium simulating the phagolysosomal environment in which Yersinia pestis resides during its intracellular growth in vivo was made by acidification of Ca2+-deficient medium. When used for cultivation of Y. pestis EV-76 (pLCR+; pPst+;pFra+) and its isogenic derivatives – KM-217 (pLCR+;pPst−;pFra−) and KM-218 (pLCR−;Ppst−; pFra−) – this medium permitted survival and proliferation of viable bacteria without any growth restriction. Moreover, a correlation between the pH of growth medium and bacterial yield was established. Acidification completely inhibited fibrinolytic (pla protease) activity (PAA) of Y. pestis carrying pPst and allowed synthesis of specific outer-membrane proteins (Yops) without any degradation by the pla protease. Comparison of whole-cell lysates of the strains tested in PAAG-SDS showed that, in addition to previously described Yops, Y. pestis synthesised new acidic proteins which appeared only under acidic conditions and were encoded by pLCR or chromosomally. Some changes in O-specific polysaccharide chains of Y. pestis LPS that were dependent on cultivation temperature and pH of the medium were also demonstrated.

Journal ArticleDOI
TL;DR: This is the first microbial isolate able to degrade a quaternary ammonium softener head group to completion and was identified by 165-rDNA sequencing as a strain of Pseudomonas putida.

Journal ArticleDOI
TL;DR: The present study evaluates the growth response of two strains of filamentous fungi, a Fusarium sp.
Abstract: The present study evaluates the growth response of two strains of filamentous fungi; a Fusarium sp. and Alternaria tenuis, grown on both solid and liquid Czapek Dox medium amended with different concentrations of CdCl2. Colony extension and the mycelial dry weight of both fungi were significantly inhibited by high concentrations of cadmium. Extended lag phases and low growth rates resulted from cadmium administration. Cadmium drastically affected fungal morphogenesis by the production of stunted sterile thick mycelial filaments of the Fusarium sp. and chains of uncharacterized swellings instead of conidia in A. tenuis. Experiments showed that cadmium accumulation by the Fusarium sp. grown in liquid medium was a concentration dependent, and over the incubation time it displayed a plateau pattern. The cells grown on medium containing 0.25 mmol l−1 CdCl2 accumulated up to 89 ± 12 μmol Cd (gm dw)−1 after two days, falling to ∼ 29 ± 10 μmol Cd (gm dw)−1 after five days. At 0.5 mmol l−1 CdCl2 treatment the maximum cellular cadmium content was ∼ 132 ± 14 μmol (gm dw)−1, attained after 3 days, and decreased to ∼98 ± 9 μmol (gm dw)−1 at the end of the incubation time. There was a simultaneous marked drop in cadmium content and pH of the growth medium during the first few days. The presence of cadmium markedly altered the cellular essential cations; K+ and Mg2+ being decreased while Na+ increased during the growth period. Such findings resulted a reverse pattern of cellular Na+/K+ ratio for cells grown on cadmium-containing medium in respect to the control treatment. The results are discussed in relation to a further dimension of cadmium effects that might reflect its toxicity, as well as the implication of cadmium extrusion for tolerance during fungal growth.

Patent
21 Sep 2001
TL;DR: In this article, a method for producing purified agar from Gelidium by bleaching it plant with sodium hypochlorate, then followed by acidifying with sulfuric acid solution, neutralizing, heating with sodium metaphosphate solution, filtrating with diatom, and dehydrating and drying the agar; filtering the aggar with a 0.2 to 0.4 micrometer microfilter; washing the filtrated agar with warm water of 20 to 70 deg.
Abstract: PURPOSE: A purified agar used for microorganism growth medium and a producing method thereof are provided, therefore the agar having the improved transparency and strength can be produced. CONSTITUTION: The method for producing purified agar comprises the steps of: producing agar from Gelidium by bleaching it plant with sodium hypochlorate, then followed by acidifying with sulfuric acid solution, neutralizing, heating with sodium metaphosphate solution, filtrating with diatom; and dehydrating and drying the agar; filtering the agar with a 0.2 to 0.4 micrometer microfilter; washing the filtrated agar with warm water of 20 to 70 deg. C; and treating the agar with an alkalic solution having pH 9.0 to 14.0 such as NaOH.

Journal ArticleDOI
TL;DR: Bovine cathepsin C production from a recombinant methylotrophic yeast Candida boidinii CT714 was investigated, and it was found that the effective vitamins were biotin, p-aminobenzoic acid and thioctic acid.
Abstract: Bovine cathepsin C (CTC) production from a recombinant methylotrophic yeast Candida boidinii CT714 was investigated, in which CTC gene was driven by formate dehydrogenase promoter and strongly induced in the presence of methanol. Two step fermentation using DYS medium containing 1.0% (w/v) glucose for cell growth and MYS medium containing 2.5% (v/v) methanol for inducible production of CTC was suitable for efficient production. Methanol concentration within 1.5 to 3.5% (v/v) was preferable for CTC induction. After 24 h of cell growth and 72 h of induction, CTC production reached approximately 12 U/I (this corresponded to 2.15 U/g-dry cells). When vitamins were enriched in growth medium, CTC productivity was improved more than 3 times higher, and it was found that the effective vitamins were biotin, p-aminobenzoic acid and thioctic acid.

Journal ArticleDOI
TL;DR: The present study showed that the microorganism required regulation of specific enzyme activities at the transcriptional level when sugar beet molasses were used as the growth medium for Z. mobilis suc40 in continuous culture.
Abstract: The osmotolerant Zymomonas mobilis strain suc40, (containing plasmid pDS3154-inaZ), which is capable of producingsimultaneously ethanol and ice nuclei protein, was cultivated in a chemically defined complete sucrosemedium, as well as in a sugar beet molasses medium in continuous culture. The strain exhibited the normalMonod's relationship between biomass and dilution rate, and between growth substrate concentration and dilutionrate. Specific activities of a number of enzymes that appear to control important steps in the metabolic flux ofthe Entner-Doudoroff and pyruvate decarboxylation pathways were investigated over a range of growth ratesin steady state cultures. With the exception of glucose-6-phosphate dehydrogenase and gluconate kinase, all ofthe enzymes exhibited a very similar pattern for the wild type Z. mobilis CP4 and for the osmotolerant mutants,independent of the media used; the enzyme patterns remained relatively constant over the studied growth range.The specific activity of glucose-6-phosphate dehydrogenase was increased 2-fold by decreasing dilution rate insugar beet molasses. The specific activity of gluconate kinase was 2-fold lower at medium growth rates comparedwith that at either low or high growth rates. Pyruvate kinase, pyruvate decarboxylase and alcohol dehydrogenaseactivities were significantly higher compared with those of the enzymes governing the early steps of the Entner-Doudoroff pathway. The present study, which was designed to determine the behaviour of important enzymes insucrosemetabolismof Z. mobilis suc40/pDS3154-inaZ grown in continuous culture showed that the microorganismrequired regulation of specific enzyme activities at the transcriptional level when sugar beet molasses were used asthe growth medium.

Journal Article
TL;DR: Sulfobacteria were shown to be resistant to stress factors, including high concentrations of Zn2+ and H+ that exceeded the optimum values, and the growth and biomass gain rates decreased, but bacteria retained their functions.
Abstract: Aerobic thermoacidophilic chemolithotrophic bacteria Sulfobacillus thermosulfidooxidans 1269T and Sulfobacillus thermosulfidooxidans subsp. asporogenes 41 were shown to be resistant to stress factors, including high concentrations of Zn2+ (0.8 M) and H+ (pH 1.2) that exceeded the optimum values. The growth and biomass gain rates decreased, but bacteria retained their functions. The activity of nearly all enzymes involved in carbon metabolism decreased. Glucose was primarily metabolized via the Entner--Doudoroff pathway. The activity tricarboxylic acid cycle enzymes decreased compared to that in cells grown under normal conditions. After saturation of the growth medium with 5 vol % CO2, sulfobacteria utilized glucose by the Embden-Meyerhof and pentose phosphate pathways under mixotrophic conditions.

Journal ArticleDOI
TL;DR: Sulfobacteria showed to be resistant to stress factors and utilized glucose by the Embden–Meyerhof and pentose phosphate pathways under mixotrophic conditions, and the activity of nearly all enzymes involved in carbon metabolism decreased.
Abstract: Aerobic thermoacidophilic chemolithotrophic bacteria Sulfobacillus thermosulfidooxidans1269Tand Sulfobacillus thermosulfidooxidanssubsp asporogenes41 were shown to be resistant to stress factors, including high concentrations of Zn2+(08 M) and supraoptimal concentrations of H+(pH 12) The growth and biomass gain rates decreased, but bacteria retained their functions The activity of nearly all enzymes involved in carbon metabolism decreased Glucose was primarily metabolized via the Entner–Doudoroff pathway The activity of tricarboxylic acid cycle enzymes decreased compared to that in cells grown under normal conditions After saturation of the growth medium with 5 vol % CO2, sulfobacteria utilized glucose by the Embden–Meyerhof and pentose phosphate pathways under mixotrophic conditions