-
Volume 142,
Issue 8,
1996
Volume 142, Issue 8, 1996
- Physiology And Growth
-
-
-
Decision phase regulation of streptomycin production in Streptomyces griseus
More LessThe streptomycin (Sm) producer, Streptomyces griseus N2-3-11, shows medium-independent biphasic kinetics of the vegetative or exponential growth phase (EGP), reflecting an innate clock-like behaviour of growth and differentiation. The S. griseus growth and development cycle has the following characteristics: (1) after the developmental cycle commences, it cannot be influenced by environmental conditions; (2) the first EGP (decision phase) and its duration seem to be genetically determined, and it is also exhibited in pleiotropic mutants deficient in differentiation and antibiotic production; (3) during this early phase of growth, the decision to produce Sm is established and the fixation of later production and differentiation can only be influenced by effector molecules, e.g. A-factor, during this period; (4) after the onset of the second EGP, the commitment to Sm production cannot be reversed by dilution into fresh medium, nor by effector molecules; (5) the length of time of this effector-insensitive growth phase (second EGP or execution phase) can be extended by dilution into fresh medium; (6) the differentiation cycle of S. griseus is completed on entering stationary phase. The cells of S. griseus then return to a decision-making stage and recover sensitivity to effector molecules. Evidence that this type of phasing is valid for the growth and developmental cycles of all streptomycetes is discussed.
-
-
-
-
Bidirectional usage of ferulate by the acetogen Peptostreptococcus productus U-1: CO2 and aromatic acrylate groups as competing electron acceptors
More LessThe influence of CO2 on the ability of Peptostreptococcus) productus U-1 (ATCC 35244) to use an aromatic acrylate group as an energy-conserving electron acceptor during O-methyl-dependent growth was examined. Ferulate (a methoxylated phenylacrylate), unlike hydroferulate (a methoxylated phenylpropionate),supported growth under CO2-limited conditions. Two phases occurred during ferulate utilization in CO2-limited cultures. In phase I (maximum growth), O-methyl-derived reductant was coupled mainly to acrylate group reduction, and acetate synthesis (CO2 as reductant sink) was minimal. In phase II, acetate synthesis increased, but cell yields in this phase were much less than in phase I. In CO2-enriched cultures, distinct phases were not observed; reductant was coupled equally to CO2 and acrylate group reduction. Under CO2-enriched conditions, O-methyl and acrylate groups were incompletely metabolized, and molar growth yields were significantly lower compared to CO2-limited conditions. Resting cell studies indicated that O-demethylase and aromatic acrylate oxidoreductase activities were induced by ferulate. These findings demonstrated that P. productus U-1 can use the aromatic acrylate oxidoreductase system as a sole, energy-conserving, electron-accepting process, but is not able to prevent the simultaneous use of the bioenergetically less favourable acetyl-CoA pathway during O-methyl-dependent growth.
-
-
-
The assimilation of sulfur from multiple sources and its correlation with expression of the sulfate-starvation-induced stimulon in Pseudomonas putida S-313
More LessConditions were optimized for the batch growth of Pseudomonas putida S-313 under sulfur-limited conditions. P. putida grew exponentially with sulfate as the sole source of sulfur, and growth was concomitant with the utilization of sulfate until it was exhausted. A further 20% of protein was synthesized after the apparent disappearance of sulfate. A mass balance for the utilized sulfate in cell material was calculated, given the observed molar growth yield of about 3·6 kg protein (mol S)−1 and a sulfur content of 0·41% S in dry matter. Similar data were obtained for growth with cysteine and thiocyanate. The organism also grew exponentially with 4-toluenesulfonate (TS) as sulfur source, essentially as observed with sulfate, except that negligible protein formation after exhaustion of TS was observed. Similar data were also obtained with 4-nitrocatecholsulfate (NCS) and ethanesulfonate. Any substrate pair selected from sulfate, cysteine and thiocyanate was utilized simultaneously, and although one of the pair of substrates was always preferred, growth continued at the same rate when only one substrate remained. Growth after substrate exhaustion was observed. Any substrate pair selected from TS, NCS and ethanesulfonate gave similar data, but with less growth after exhaustion of the sulfur sources. If a mixed substrate pair was chosen from the two groups, the sulfur source from the first-named group was initially used exclusively, and the second source of sulfur was utilized subsequently, after a lag phase. The data are considered to reflect the control of scavenging for sulfur and of distribution of sulfur in the cell exerted by the sulfate-starvation-induced stimulon [Kertesz, Leisinger & Cook, J Bacteriol (1993) 175, 1187-1189].
-
-
-
Physiological effects of nitrogen starvation in an anaerobic batch culture of Saccharomyces cerevisiae
More LessThe effects of nitrogen starvation on the anaerobic physiology of Saccharomyces cerevisiae were studied in cells cultivated in a bioreactor. The composition of the mineral medium was designed such that the nitrogen source became depleted while there was still ample glucose left in the medium. The culture was characterized by acoustic gas analysis, flow injection analysis and HPLC analysis of extracellular substrates and metabolites. During the cultivation, the macromolecular composition of the cells was analysed with respect to the cellular content of RNA, protein, trehalose and glycogen. During exponential growth under anaerobic conditions, the maximum specific growth rate (μmax) of S. cerevisiae CBS 8066 (0·46 h-1) was identical to the μmax determined under aerobic conditions. Depletion of ammonium in the medium led to an abrupt decrease in the flux through glycolysis. Subsequently, a continuous decrease in the carbon dioxide evolution rate, caused by catabolite inactivation of the hexose-transport system, was observed. The apparent half-life of the transport system under nitrogen starvation was 13 h. During the exponential growth phase, the cellular content of RNA and protein was 15% (w/w) and 60% (w/w), respectively. At the end of the cultivation where the cells had been starved of nitrogen for 18 h, the cellular content of RNA and protein had decreased to 4% (w/w) and 22% (w/w), respectively. The intracellular carbohydrate content increased dramatically as trehalose and glycogen accumulated to final concentrations of 7% (w/w) and 25% (w/w), respectively. Glycerol formation during nitrogen starvation was higher than that accounted for by the formation of organic acids, suggesting a protein turnover of approximately 6% h−1. The growth energetics of S. cerevisiae CBS 8066 also changed as a result of nitrogen starvation, and Y xATP was observed to increase from 80 mmol g−1 during the exponential growth phase to more than 130 mmol g−1 towards the end of the cultivation. The presented results illustrate the effect of nitrogen starvation on glycerol formation, protein turnover, catabolite inactivation of the sugar-transport system, the cellular composition, the cell cycle and growth energetics.
-
- Plant-Microbe Interactions
-
-
-
Endophytic taxol-producing fungi from bald cypress, Taxodium distichum
More LessPestalotiopsis microspora occurs as a range of strains in bald cypress, Taxodium distichum. The organisms live as endophytes in the bark, phloem and xylem, and isolates show differences in cultural and microscopic characteristics on common laboratory media. Many of these fungi make taxol as determined by the reactivity of partially purified culture extracts with specific monoclonal antibodies against taxol. In the case of one strain of P. microspora (CP-4), taxol was isolated from culture medium and was shown to be identical to authentic taxol by chromatographic and spectroscopic means.
-
-
- Genome Analysis
-
-
-
Sequence analysis of the Bacillus subtilis chromosome region between the serA and kdg loci cloned in a yeast artificial chromosome
The standard strategies of genome sequencing based on λ-vector or cosmid libraries are only partially applicable to AT-rich Gram-positive bacteria because of the problem of instability of their chromosomal DNA in heterologous hosts like Escherichia coli . One complete collection of ordered clones known for such bacteria is that of Bacillus subtilis, established by using yeast artificial chromosomes (YACs). This paper reports the results of the direct use of one of the YAC clones from the above collection for the sequencing of the region cloned in it. The strategy applied consisted of the following: (i) construction of M13 banks of the partially purified YAC DNA and sequencing of 800 M13 clones chosen at random; (ii) directed selection of M13 clones to sequence by using marginal contig fragments as hybridization probes; (iii) direct sequencing of joining PCR fragments obtained by combinations of primers corresponding to the ends of representative contigs. The complete 104 109 bp insert sequence of this YAC clone was thus established. The strategy used allowed us to avoid resequencing the two largest, previously sequenced, contigs (13695 and 20303 bp) of the YAC insert. We propose that the strategy used can be applied to the sequencing of the whole bacterial genome without intermediate cloning, as well as for larger inserts of eukaryotic origin cloned ir YACs. Sequencing of the insert of the YAC clone 15-6B allowed us to establish the contiguous sequence of 127 kb from spollA to kdg. The organization of the newly determined region is presented. Of the 138 ORFs identified in the spollA-kdg region, 57 have no clear putative function from their homology to proteins in the databases.
-
-
-
-
A Bacillus subtilis gene cluster similar to the Escherichia coli phosphate-specific transport (pst) operon: evidence for a tandemly arranged pstB gene
More LessWe have determined the complete nucleotide sequence of the Bacillus subtilis homologues of the Escherichia coli phosphate-specific transport (pst) genes in the framework of the international B. subtilis genome sequencing project. The pst genes in E. coli form an operon arranged in the order pstS, pstC, pstA, pstB and phoU . In the case of B. subtilis, there are also five ORFs presumably forming an operon. The deduced amino acid sequences of the products of these ORFs show striking similarities to their E. coli counterparts. Comparison of the organization of the pst operon of B. subtilis with that of E. coli revealed that the gene corresponding to phoU is missing, while there are two genes homologous to pstB in B. subtilis. The pst operon is located at 222° on the B. subtilis chromosome
-
Volumes and issues
-
Volume 171 (2025)
-
Volume 170 (2024)
-
Volume 169 (2023)
-
Volume 168 (2022)
-
Volume 167 (2021)
-
Volume 166 (2020)
-
Volume 165 (2019)
-
Volume 164 (2018)
-
Volume 163 (2017)
-
Volume 162 (2016)
-
Volume 161 (2015)
-
Volume 160 (2014)
-
Volume 159 (2013)
-
Volume 158 (2012)
-
Volume 157 (2011)
-
Volume 156 (2010)
-
Volume 155 (2009)
-
Volume 154 (2008)
-
Volume 153 (2007)
-
Volume 152 (2006)
-
Volume 151 (2005)
-
Volume 150 (2004)
-
Volume 149 (2003)
-
Volume 148 (2002)
-
Volume 147 (2001)
-
Volume 146 (2000)
-
Volume 145 (1999)
-
Volume 144 (1998)
-
Volume 143 (1997)
-
Volume 142 (1996)
-
Volume 141 (1995)
-
Volume 140 (1994)
-
Volume 139 (1993)
-
Volume 138 (1992)
-
Volume 137 (1991)
-
Volume 136 (1990)
-
Volume 135 (1989)
-
Volume 134 (1988)
-
Volume 133 (1987)
-
Volume 132 (1986)
-
Volume 131 (1985)
-
Volume 130 (1984)
-
Volume 129 (1983)
-
Volume 128 (1982)
-
Volume 127 (1981)
-
Volume 126 (1981)
-
Volume 125 (1981)
-
Volume 124 (1981)
-
Volume 123 (1981)
-
Volume 122 (1981)
-
Volume 121 (1980)
-
Volume 120 (1980)
-
Volume 119 (1980)
-
Volume 118 (1980)
-
Volume 117 (1980)
-
Volume 116 (1980)
-
Volume 115 (1979)
-
Volume 114 (1979)
-
Volume 113 (1979)
-
Volume 112 (1979)
-
Volume 111 (1979)
-
Volume 110 (1979)
-
Volume 109 (1978)
-
Volume 108 (1978)
-
Volume 107 (1978)
-
Volume 106 (1978)
-
Volume 105 (1978)
-
Volume 104 (1978)
-
Volume 103 (1977)
-
Volume 102 (1977)
-
Volume 101 (1977)
-
Volume 100 (1977)
-
Volume 99 (1977)
-
Volume 98 (1977)
-
Volume 97 (1976)
-
Volume 96 (1976)
-
Volume 95 (1976)
-
Volume 94 (1976)
-
Volume 93 (1976)
-
Volume 92 (1976)
-
Volume 91 (1975)
-
Volume 90 (1975)
-
Volume 89 (1975)
-
Volume 88 (1975)
-
Volume 87 (1975)
-
Volume 86 (1975)
-
Volume 85 (1974)
-
Volume 84 (1974)
-
Volume 83 (1974)
-
Volume 82 (1974)
-
Volume 81 (1974)
-
Volume 80 (1974)
-
Volume 79 (1973)
-
Volume 78 (1973)
-
Volume 77 (1973)
-
Volume 76 (1973)
-
Volume 75 (1973)
-
Volume 74 (1973)
-
Volume 73 (1972)
-
Volume 72 (1972)
-
Volume 71 (1972)
-
Volume 70 (1972)
-
Volume 69 (1971)
-
Volume 68 (1971)
-
Volume 67 (1971)
-
Volume 66 (1971)
-
Volume 65 (1971)
-
Volume 64 (1970)
-
Volume 63 (1970)
-
Volume 62 (1970)
-
Volume 61 (1970)
-
Volume 60 (1970)
-
Volume 59 (1969)
-
Volume 58 (1969)
-
Volume 57 (1969)
-
Volume 56 (1969)
-
Volume 55 (1969)
-
Volume 54 (1968)
-
Volume 53 (1968)
-
Volume 52 (1968)
-
Volume 51 (1968)
-
Volume 50 (1968)
-
Volume 49 (1967)
-
Volume 48 (1967)
-
Volume 47 (1967)
-
Volume 46 (1967)
-
Volume 45 (1966)
-
Volume 44 (1966)
-
Volume 43 (1966)
-
Volume 42 (1966)
-
Volume 41 (1965)
-
Volume 40 (1965)
-
Volume 39 (1965)
-
Volume 38 (1965)
-
Volume 37 (1964)
-
Volume 36 (1964)
-
Volume 35 (1964)
-
Volume 34 (1964)
-
Volume 33 (1963)
-
Volume 32 (1963)
-
Volume 31 (1963)
-
Volume 30 (1963)
-
Volume 29 (1962)
-
Volume 28 (1962)
-
Volume 27 (1962)
-
Volume 26 (1961)
-
Volume 25 (1961)
-
Volume 24 (1961)
-
Volume 23 (1960)
-
Volume 22 (1960)
-
Volume 21 (1959)
-
Volume 20 (1959)
-
Volume 19 (1958)
-
Volume 18 (1958)
-
Volume 17 (1957)
-
Volume 16 (1957)
-
Volume 15 (1956)
-
Volume 14 (1956)
-
Volume 13 (1955)
-
Volume 12 (1955)
-
Volume 11 (1954)
-
Volume 10 (1954)
-
Volume 9 (1953)
-
Volume 8 (1953)
-
Volume 7 (1952)
-
Volume 6 (1952)
-
Volume 5 (1951)
-
Volume 4 (1950)
-
Volume 3 (1949)
-
Volume 2 (1948)
-
Volume 1 (1947)
Most Read This Month
