scholarly journals Effects of cofD gene knock-out on the methanogenesis of Methanobrevibacter ruminantium

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jian Ma ◽  
Xueying Wang ◽  
Ting Zhou ◽  
Rui Hu ◽  
Huawei Zou ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Production Capacity ◽  
Maximum Amount ◽  
Logarithmic Phase ◽  
Wild Type ◽  
Knock Out ◽  
Maximum Biomass ◽  
Reproductive Ability ◽  
Methanobrevibacter Ruminantium

AbstractThis study aimed to investigate the effects of cofD gene knock-out on the synthesis of coenzyme F420 and production of methane in Methanobrevibacter ruminantium (M. ruminantium). The experiment successfully constructed a cofD gene knock-out M. ruminantium via homologous recombination technology. The results showed that the logarithmic phase of mutant M. ruminantium (12 h) was lower than the wild-type (24 h). The maximum biomass and specific growth rate of mutant M. ruminantium were significantly lower (P < 0.05) than those of wild-type, and the maximum biomass of mutant M. ruminantium was approximately half of the wild-type; meanwhile, the proliferation was reduced. The synthesis amount of coenzyme F420 of M. ruminantium was significantly decreased (P < 0.05) after the cofD gene knock-out. Moreover, the maximum amount of H2 consumed and CH4 produced by mutant were 14 and 2% of wild-type M. ruminantium respectively. In conclusion, cofD gene knock-out induced the decreased growth rate and reproductive ability of M. ruminantium. Subsequently, the synthesis of coenzyme F420 was decreased. Ultimately, the production capacity of CH4 in M. ruminantium was reduced. Our research provides evidence that cofD gene plays an indispensable role in the regulation of coenzyme F420 synthesis and CH4 production in M. ruminantium.

scholarly journals Growth performance of siamese gourami Trichopodus pectoralis seed with different stocking density to optimize production capacity: optimum temperature and salinity application

2018 ◽  
Vol 47 ◽  
pp. 02007
Author(s):  
Lies Setijaningsih ◽  
Dewi Puspaningsih ◽  
Imam Taufik
Keyword(s):  
Growth Rate ◽  
Survival Rate ◽  
Specific Growth Rate ◽  
Growth Performance ◽  
Specific Growth ◽  
Production Capacity ◽  
Stocking Density ◽  
Optimum Temperature ◽  
Slow Growth Rate ◽  
Randomized Design

Fulfill needs of Siamese gourami still rely on the catch from nature, so the population in nature has become decreased. The increase of Siamese gourami fish production from culture is still constrained by the survival rate and slow growth rate in the seed phase. The purpose of this research was to determine the effect of Siamese gourami stocking density on the application of optimum temperature and salinity to growth performance for optimization of production capacity. Application of optimum temperature and salinity refers to the results of previous research, i.e., temperature of 28 °C and salinity 3 ‰. Siamese gourami seed with length of 2.96 ± 0.42 cm and weight of 5.27 ± 0.10 g used in the research. The experimental design used completely randomized design with four treatments, i.e. 1 fish L-1, 2 fish L-1, 3 fish L-1 and 4 fish L-1. The results showed that there were an effect of different stocking density on absolute growth weight and length, survival rate, specific growth rate and productivity. This is shown in the C treatment which growth was 4.95 ± 0.037 g, length 3.51 ± 0.01 cm, survival rate 93.47%, specific growth rate 1.22% and fish productivity of 625.76 g.

Rhizoremediation of Trichloroethylene by a Recombinant, Root-Colonizing Pseudomonas fluorescensStrain Expressing Toluene ortho-Monooxygenase Constitutively

1998 ◽  
Vol 64 (1) ◽  
pp. 112-118 ◽  
Author(s):  
Dennis C. Yee ◽  
Jennifer A. Maynard ◽  
Thomas K. Wood
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Burkholderia Cepacia ◽  
Specific Growth ◽  
Initial Rate ◽  
Protein A ◽  
Maximum Specific Growth Rate ◽  
Wild Type ◽  
Sterile Soil ◽  
Negative Controls

ABSTRACT Trichloroethylene (TCE) was removed from soils by using a wheat rhizosphere established by coating seeds with a recombinant, TCE-degrading Pseudomonas fluorescens strain that expresses the tomA + (tolueneo-monooxygenase) genes from Burkholderia cepacia PR123(TOM23C). A transposon integration vector was used to insert tomA +into the chromosome of P. fluorescens 2-79, producing a stable strain that expressed constitutively the monooxygenase at a level of 1.1 nmol/min · mg of protein (initial TCE concentration, 10 μM, assuming that all of the TCE was in the liquid) for more than 280 cell generations (36 days). We also constructed a salicylate-inducible P. fluorescens strain that degraded TCE at an initial rate of 2.6 nmol/min · mg of protein in the presence of 10 μM TCE [cf. B. cepacia G4 PR123(TOM23C), which degraded TCE at an initial rate of 2.5 nmol/min · mg of protein]. A constitutive strain,P. fluorescens 2-79TOM, grew (maximum specific growth rate, 0.78 h−1) and colonized wheat (3 × 106CFU/cm of root) as well as wild-type P. fluorescens 2-79 (maximum specific growth rate, 0.77 h−1; level of colonization, 4 × 106 CFU/cm of root). Rhizoremediation of TCE was demonstrated by using microcosms containing the constitutive monooxygenase-expressing microorganism, soil, and wheat. These closed microcosms degraded an average of 63% of the initial TCE in 4 days (20.6 nmol of TCE/day · plant), compared to the 9% of the initial TCE removed by negative controls consisting of microcosms containing wild-type P. fluorescens2-79-inoculated wheat, uninoculated wheat, or sterile soil.

Impact of Nitrogen Source on the Growth, Specific Growth Rate and Lipid Synthesis of Monoraphidium sp.FXY-10 under Different Culture Conditions

2013 ◽  
Vol 864-867 ◽  
pp. 71-78
Author(s):  
Ke Ding ◽  
Tao Li ◽  
Peng Zhao ◽  
Lin Wang ◽  
Xu Ya Yu
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Nitrogen Source ◽  
Lipid Content ◽  
Specific Growth ◽  
Lipid Synthesis ◽  
Culture Conditions ◽  
Optimal Conditions ◽  
Maximum Biomass ◽  
The Impact

The NaNO3concentration influencing the growth and lipid synthesis ofMonoraphidiumsp.FXY-10 under three cultures (autotrophy, heterotrophy and mixotrophy) was studied through flask-shaking experiment. Additionally, the impact of nitrogen source on the growth and lipid content ofMonoraphidiumsp.FXY-10 was investigated. The NaNO3concentration for maximum biomass and highest lipid content ofMonoraphidiumsp.FXY-10 was obtained and the optimal conditions for its N absorption were concluded through the Andrew model.

scholarly journals Physiological Role of β-Phosphoglucomutase inLactococcus lactis

2001 ◽  
Vol 67 (10) ◽  
pp. 4546-4553 ◽  
Author(s):  
Fredrik Levander ◽  
Ulrika Andersson ◽  
Peter Rådström
Keyword(s):  
Growth Rate ◽  
Carbon Source ◽  
Specific Growth Rate ◽  
Type Strain ◽  
Wild Type Strain ◽  
Specific Growth ◽  
Maximum Specific Growth Rate ◽  
Wild Type ◽  
Cell Extracts

ABSTRACT A β-phosphoglucomutase (β-PGM) mutant of Lactococcus lactis subsp. lactis ATCC 19435 was constructed using a minimal integration vector and double-crossover recombination. The mutant and the wild-type strain were grown under controlled conditions with different sugars to elucidate the role of β-PGM in carbohydrate catabolism and anabolism. The mutation did not significantly affect growth, product formation, or cell composition when glucose or lactose was used as the carbon source. With maltose or trehalose as the carbon source the wild-type strain had a maximum specific growth rate of 0.5 h−1, while the deletion of β-PGM resulted in a maximum specific growth rate of 0.05 h−1 on maltose and no growth at all on trehalose. Growth of the mutant strain on maltose resulted in smaller amounts of lactate but more formate, acetate, and ethanol, and approximately 1/10 of the maltose was found as β-glucose 1-phosphate in the medium. Furthermore, the β-PGM mutant cells grown on maltose were considerably larger and accumulated polysaccharides which consisted of α-1,4-bound glucose units. When the cells were grown at a low dilution rate in a glucose and maltose mixture, the wild-type strain exhibited a higher carbohydrate content than when grown at higher growth rates, but still this content was lower than that in the β-PGM mutant. In addition, significant differences in the initial metabolism of maltose and trehalose were found, and cell extracts did not digest free trehalose but only trehalose 6-phosphate, which yielded β-glucose 1-phosphate and glucose 6-phosphate. This demonstrates the presence of a novel enzymatic pathway for trehalose different from that of maltose metabolism in L. lactis.

scholarly journals Identification of Enzymes and Quantification of Metabolic Fluxes in the Wild Type and in a Recombinant Aspergillus oryzae Strain

1999 ◽  
Vol 65 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Henrik Pedersen ◽  
Morten Carlsen ◽  
Jens Nielsen
Keyword(s):  
Growth Rate ◽  
Pentose Phosphate Pathway ◽  
Isocitrate Dehydrogenase ◽  
Type Strain ◽  
Wild Type Strain ◽  
Specific Growth ◽  
Pentose Phosphate ◽  
Central Metabolism ◽  
Wild Type ◽  
Metabolic Fluxes

ABSTRACT Two α-amylase-producing strains of Aspergillus oryzae, a wild-type strain and a recombinant containing additional copies of the α-amylase gene, were characterized with respect to enzyme activities, localization of enzymes to the mitochondria or cytosol, macromolecular composition, and metabolic fluxes through the central metabolism during glucose-limited chemostat cultivations. Citrate synthase and isocitrate dehydrogenase (NAD) activities were found only in the mitochondria, glucose-6-phosphate dehydrogenase and glutamate dehydrogenase (NADP) activities were found only in the cytosol, and isocitrate dehydrogenase (NADP), glutamate oxaloacetate transaminase, malate dehydrogenase, and glutamate dehydrogenase (NAD) activities were found in both the mitochondria and the cytosol. The measured biomass components and ash could account for 95% (wt/wt) of the biomass. The protein and RNA contents increased linearly with increasing specific growth rate, but the carbohydrate and chitin contents decreased. A metabolic model consisting of 69 fluxes and 59 intracellular metabolites was used to calculate the metabolic fluxes through the central metabolism at several specific growth rates, with ammonia or nitrate as the nitrogen source. The flux through the pentose phosphate pathway increased with increasing specific growth rate. The fluxes through the pentose phosphate pathway were 15 to 26% higher for the recombinant strain than for the wild-type strain.

scholarly journals A Cytochrome cbb3(Cytochrome c) Terminal Oxidase in Azospirillum brasilense Sp7 Supports Microaerobic Growth

1998 ◽  
Vol 180 (21) ◽  
pp. 5689-5696 ◽  
Author(s):  
Kathleen Marchal ◽  
Jun Sun ◽  
Veerle Keijers ◽  
Huub Haaker ◽  
Jos Vanderleyden
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Respiration Rate ◽  
Growth Rates ◽  
Azospirillum Brasilense ◽  
Specific Growth ◽  
Limiting Factor ◽  
Nitrogen Fixing ◽  
Wild Type ◽  
Microaerobic Conditions

ABSTRACT Spectral analysis indicated the presence of a cytochromecbb 3 oxidase under microaerobic conditions inAzospirillum brasilense Sp7 cells. The corresponding genes (cytNOQP) were isolated by using PCR. These genes are organized in an operon, preceded by a putative anaerobox. The phenotype of an A. brasilense cytN mutant was analyzed. Under aerobic conditions, the specific growth rate during exponential phase (μe) of the A. brasilense cytNmutant was comparable to the wild-type specific growth rate (μe of approximately 0.2 h−1). In microaerobic NH4 +-supplemented conditions, the low respiration of the A. brasilense cytN mutant affected its specific growth rate (μe of approximately 0.02 h−1) compared to the wild-type specific growth rate (μe of approximately 0.2 h−1). Under nitrogen-fixing conditions, both the growth rates and respiration of the wild type were significantly diminished in comparison to those under NH4 +-supplemented conditions. Differences in growth rates and respiration between the wild type and theA. brasilense cytN mutant were less pronounced under these nitrogen-fixing conditions (μe of approximately 0.03 h−1 for the wild type and 0.02 h−1 for the A. brasilense cytN mutant). The nitrogen-fixing capacity of the A. brasilense cytN mutant was still approximately 80% of that determined for the wild-type strain. This leads to the conclusion that the A. brasilensecytochrome cbb 3 oxidase is required under microaerobic conditions, when a high respiration rate is needed, but that under nitrogen-fixing conditions the respiration rate does not seem to be a growth-limiting factor.

Functional characterization of the H+/K+ ATPase in wild type and gastrin knock-out mice

2007 ◽  
Vol 45 (05) ◽  
Author(s):  
A Schnur ◽  
P Hegyi ◽  
V Venglovecz ◽  
Z Rakonczay ◽  
I Ignáth ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Wild Type ◽  
Knock Out ◽  
Knock Out Mice

Oscillating conditions for influencing the composition of mixed biological cultures

1998 ◽  
Vol 37 (4-5) ◽  
pp. 259-262 ◽  
Author(s):  
Bjarne R. Horntvedt ◽  
Morten Rambekk ◽  
Rune Bakke
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Heterotrophic Bacteria ◽  
Bacterial Species ◽  
Rate Reduction ◽  
Similar Strategy ◽  
Sinusoidal Oscillations ◽  
Specific Growth Rates ◽  
Rate Limiting ◽  
Concentration Levels

This paper presents a strategy in which mixed biological cultures are exposed to oscillating concentration levels, to improve the potential for coexistence of desired bacterial species. A mechanistic mathematical model is constructed to investigate and illustrate this strategy. This paper is focused on competition between nitrifying, denitrifying and aerobic heterotrophic bacteria in a CSTR with sludge recycle. For nitrifying and aerobic heterotrophic cultures, the effect of sinusoidal oscillations in DO levels with an amplitude of 1.0 mg/l is a 16% specific growth rate reduction compared to that at a constant DO level. The denitrifiers growth rate is increased by an average of 59%, compared to the constant DO level situation. A similar strategy has been tested in a pilot plant. It is concluded that the influence on specific growth rates is a function of the amplitude of the oscillations. The effects are greatest when concentrations fluctuate around the half saturation concentration of the rate limiting component(s).

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