Effects of pH on the growth rate exhibited of the wild-type and Cd-resistant Dictyosphaerium chlorelloides strains

Limnetica ◽  
2018 ◽  
pp. 229-238
Author(s):  
Cortés, Alondra A. ◽  
Sánchez-Fortún, Sebastián ◽  
García, Martha ◽  
Bartolomé, Mª Carmen
Keyword(s):  
Growth Rate ◽  
Wild Type ◽  
Effects Of Ph ◽  
Dictyosphaerium Chlorelloides

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 The Constitutive Centromere Component CENP-50 Is Required for Recovery from Spindle Damage

2005 ◽  
Vol 25 (23) ◽  
pp. 10315-10328 ◽  
Author(s):  
Yukinori Minoshima ◽  
Tetsuya Hori ◽  
Masahiro Okada ◽  
Hiroshi Kimura ◽  
Tokuko Haraguchi ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Growth Rate ◽  
Mitotic Checkpoint ◽  
Loss Of Function ◽  
Wild Type ◽  
Centromere Function ◽  
Dt40 Cells ◽  
Precise Role ◽  
Chicken Dt40 Cell

ABSTRACT We identified CENP-50 as a novel kinetochore component. We found that CENP-50 is a constitutive component of the centromere that colocalizes with CENP-A and CENP-H throughout the cell cycle in vertebrate cells. To determine the precise role of CENP-50, we examined its role in centromere function by generating a loss-of-function mutant in the chicken DT40 cell line. The CENP-50 knockout was not lethal; however, the growth rate of cells with this mutation was slower than that of wild-type cells. We observed that the time for CENP-50-deficient cells to complete mitosis was longer than that for wild-type cells. Centromeric localization of CENP-50 was abolished in both CENP-H- and CENP-I-deficient cells. Coimmunoprecipitation experiments revealed that CENP-50 interacted with the CENP-H/CENP-I complex in chicken DT40 cells. We also observed severe mitotic defects in CENP-50-deficient cells with apparent premature sister chromatid separation when the mitotic checkpoint was activated, indicating that CENP-50 is required for recovery from spindle damage.

scholarly journals Impaired Temperature Stress Response of a Streptococcus thermophilus deoD Mutant

2003 ◽  
Vol 69 (2) ◽  
pp. 1287-1289 ◽  
Author(s):  
Mario Varcamonti ◽  
Maria R. Graziano ◽  
Romilde Pezzopane ◽  
Gino Naclerio ◽  
Slavica Arsenijevic ◽  
...  
Keyword(s):  
Growth Rate ◽  
Stress Response ◽  
Heat Shock ◽  
Temperature Stress ◽  
Streptococcus Thermophilus ◽  
Wild Type ◽  
Temperature Shock ◽  
Dual Response ◽  
Survival Capacity

ABSTRACT An insertional deoD mutant of Streptococcus thermophilus strain SFi39 had a reduced growth rate at 20°C and an enhanced survival capacity to heat shock compared to the wild type, indicating that the deoD product is involved in temperature shock adaptation. We report evidence that ppGpp is implicated in this dual response.

scholarly journals Effect of Organic Solvents on the Yield of Solvent-Tolerant Pseudomonas putida S12

1999 ◽  
Vol 65 (6) ◽  
pp. 2631-2635 ◽  
Author(s):  
Sonja Isken ◽  
Antoine Derks ◽  
Petra F. G. Wolffs ◽  
Jan A. M. de Bont
Keyword(s):  
Growth Rate ◽  
Pseudomonas Putida ◽  
Organic Solvents ◽  
Critical Concentration ◽  
Bacterial Membrane ◽  
Maximal Growth ◽  
Wild Type ◽  
Active Efflux ◽  
Maximal Growth Rate ◽  
Solvent Tolerant

ABSTRACT Solvent-tolerant microorganisms are useful in biotransformations with whole cells in two-phase solvent-water systems. The results presented here describe the effects that organic solvents have on the growth of these organisms. The maximal growth rate of Pseudomonas putida S12, 0.8 h−1, was not affected by toluene in batch cultures, but in chemostat cultures the solvent decreased the maximal growth rate by nearly 50%. Toluene, ethylbenzene, propylbenzene, xylene, hexane, and cyclohexane reduced the biomass yield, and this effect depended on the concentration of the solvent in the bacterial membrane and not on its chemical structure. The dose response to solvents in terms of yield was linear up to an approximately 200 mM concentration of solvent in the bacterial membrane, both in the wild type and in a mutant lacking an active efflux system for toluene. Above this critical concentration the yield of the wild type remained constant at 0.2 g of protein/g of glucose with increasing concentrations of toluene. The reduction of the yield in the presence of solvents is due to a maintenance higher by a factor of three or four as well as to a decrease of the maximum growth yield by 33%. Therefore, energy-consuming adaptation processes as well as the uncoupling effect of the solvents reduce the yield of the tolerant cells.

scholarly journals The effect of calnexin deletion on the expression level of PDI in Saccharomyces cerevisiae under heat stress conditions

2008 ◽  
Vol 13 (1) ◽  
Author(s):  
Huili Zhang ◽  
Jianwei He ◽  
Yanyan Ji ◽  
Akio Kato ◽  
Youtao Song
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Growth Rate ◽  
Heat Stress ◽  
Protein Expression ◽  
Molecular Chaperone ◽  
Mrna Level ◽  
Stress Conditions ◽  
Mrna Levels ◽  
Wild Type ◽  
Wild Type Yeast

AbstractWe cultured calnexin-disrupted and wild-type Saccharomyces cerevisiae strains under conditions of heat stress. The growth rate of the calnexin-disrupted yeast was almost the same as that of the wild-type yeast under those conditions. However, the induced mRNA level of the molecular chaperone PDI in the ER was clearly higher in calnexin-disrupted S. cerevisiae relative to the wild type at 37°C, despite being almost the same in the two strains under normal conditions. The western blotting analysis for PDI protein expression in the ER yielded results that show a parallel in their mRNA levels in the two strains. We suggest that PDI may interact with calnexin under heat stress conditions, and that the induction of PDI in the ER can recover part of the function of calnexin in calnexin-disrupted yeast, and result in the same growth rate as in wild-type yeast.

scholarly journals Identification and Functional Analysis of the Gene Cluster for l-Arabinose Utilization in Corynebacterium glutamicum

2009 ◽  
Vol 75 (11) ◽  
pp. 3419-3429 ◽  
Author(s):  
Hideo Kawaguchi ◽  
Miho Sasaki ◽  
Alain A. Vertès ◽  
Masayuki Inui ◽  
Hideaki Yukawa
Keyword(s):  
Growth Rate ◽  
Corynebacterium Glutamicum ◽  
Gene Cluster ◽  
Wild Type Strain ◽  
Transcriptional Regulator ◽  
Transcriptional Unit ◽  
Gene Products ◽  
Wild Type ◽  
Mutant Cells ◽  
Arabinose Isomerase

ABSTRACT Corynebacterium glutamicum ATCC 31831 grew on l-arabinose as the sole carbon source at a specific growth rate that was twice that on d-glucose. The gene cluster responsible for l-arabinose utilization comprised a six-cistron transcriptional unit with a total length of 7.8 kb. Three l-arabinose-catabolizing genes, araA (encoding l-arabinose isomerase), araB (l-ribulokinase), and araD (l-ribulose-5-phosphate 4-epimerase), comprised the araBDA operon, upstream of which three other genes, araR (LacI-type transcriptional regulator), araE (l-arabinose transporter), and galM (putative aldose 1-epimerase), were present in the opposite direction. Inactivation of the araA, araB, or araD gene eliminated growth on l-arabinose, and each of the gene products was functionally homologous to its Escherichia coli counterpart. Moreover, compared to the wild-type strain, an araE disruptant exhibited a >80% decrease in the growth rate at a lower concentration of l-arabinose (3.6 g liter−1) but not at a higher concentration of l-arabinose (40 g liter−1). The expression of the araBDA operon and the araE gene was l-arabinose inducible and negatively regulated by the transcriptional regulator AraR. Disruption of araR eliminated the repression in the absence of l-arabinose. Expression of the regulon was not repressed by d-glucose, and simultaneous utilization of l-arabinose and d-glucose was observed in aerobically growing wild-type and araR deletion mutant cells. The regulatory mechanism of the l-arabinose regulon is, therefore, distinct from the carbon catabolite repression mechanism in other bacteria.

Effects of pH on the growth rate, motility and photosynthesis inEuglena gracilis

2001 ◽  
Vol 46 (6) ◽  
pp. 549-554 ◽  
Author(s):  
R. A. Danilov ◽  
N. G. A. Ekelund
Keyword(s):  
Growth Rate ◽  
Effects Of Ph

scholarly journals Overexpression of an activated rasG gene during growth blocks the initiation of Dictyostelium development.

1996 ◽  
Vol 16 (8) ◽  
pp. 4156-4162 ◽  
Author(s):  
M Khosla ◽  
G B Spiegelman ◽  
G Weeks
Keyword(s):  
Growth Rate ◽  
Cell Growth ◽  
Cyclic Amp ◽  
Dominant Negative ◽  
Differentiation Process ◽  
Fruiting Bodies ◽  
Wild Type ◽  
Ras Protein ◽  
Initial Generation ◽  
Type Strains

Transformants that expressed either the wild-type rasG gene, an activated rasG-G12T gene, or a dominant negative rasG-S17N gene, all under the control of the folate-repressible discoidin (dis1gamma) promoter, were isolated. All three transformants expressed high levels of Ras protein which were reduced by growth in the presence of folate. All three transformants grew slowly, and the reduction in growth rate correlated with the amount of RasG protein produced, suggesting that RasG is important in regulating cell growth. The pVEII-rasG transformant containing the wild-type rasG gene developed normally despite the presence of high levels of RasG throughout development. This result indicates that the down regulation of rasG that normally occurs during aggregation of wild-type strains is not essential for the differentiation process. Dictyostelium transformants expressing the dominant negative rasG-S17N gene also differentiated normally. Dictyostelium transformants that overexpressed the activated rasG-G12T gene did not aggregate. The defect occurred very early in development, since the expression of car1 and pde, genes that are normally induced soon after the initiation of development, was repressed. However, when the transformant cells were pulsed with cyclic AMP, expression of both genes returned to wild-type levels. The transformants exhibited chemotaxis to cyclic AMP, and development was synergized by mixing with wild-type cells. Furthermore, cells that were pulsed with cyclic AMP for 4 h before being induced to differentiate by plating on filters produced small, but otherwise normal, fruiting bodies. These results suggest that the rasG-G12T transformants are defective in cyclic AMP production and that RasG - GTP blocks development by interfering with the initial generation of cyclic AMP pulses.

Growth experiments on morphological mutants of Gracilaria tikvahiae (Rhodophyceae)

1983 ◽  
Vol 61 (6) ◽  
pp. 1654-1659 ◽  
Author(s):  
Mohsin U. Patwary ◽  
John P. van der Meer
Keyword(s):  
Growth Rate ◽  
High Density ◽  
Low Density ◽  
Wild Type ◽  
Gracilaria Tikvahiae ◽  
Morphological Mutants ◽  
Growth Experiments

The growth of morphological mutants of Gracilaria tikvahiae was compared with that of wild-type clones in tanks of flowing seawater in a greenhouse. At low density four mutants grew faster than a related wild type, and two, MP-40 and MP-44, grew faster than any of the wild clones tested. Of the mutants, MP-40 consistently had the fastest growth rate at low density. At high density MP-40 and MP-44 again grew faster than wild type; however, MP-44 had the faster growth rate and gave the higher yields. Both of these mutants removed nitrogen (NH4+) from seawater faster than the wild types and both proved to be much more epiphyte resistant, with MP-40 scoring highest for both of these characteristics.

Sign in / Sign up

Export Citation Format

Share Document