Dietary tryptophan and the selection of ethyl alcohol in different strains of rats

1975 ◽  
Vol 42 (2) ◽  
pp. 109-115 ◽  
Author(s):  
R. D. Myers ◽  
Christine L. Melchior
Keyword(s):  
Ethyl Alcohol ◽  
Different Strains ◽  
Selection Of

Impact of elevated CO2 on carbohydrate and ureide concentrations in soybean inoculated with different strains of Bradyrhizobium japonicum

Botany ◽  
2011 ◽  
Vol 89 (7) ◽  
pp. 481-490 ◽  
Author(s):  
Annick Bertrand ◽  
Danielle Prévost ◽  
Christine Juge ◽  
François-P. Chalifour
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Feedback Inhibition ◽  
Nitrogenase Activity ◽  
Soluble Sugars ◽  
Dry Mass ◽  
Energy Reserves ◽  
Commercial Strain ◽  
Growth Chambers ◽  
Different Strains ◽  
Selection Of

Elevated CO2 increases soybean growth and photosynthesis, and the resulting additional supply of photosynthates stimulates nodule activity. To characterize its biochemical response to both CO2 and bradyrhizobial strains, soybean inoculated with three strains of Bradyrhizobium japonicum was grown in growth chambers under ambient (400 µmol·mol–1) or elevated (800 µmol·mol–1) CO2. Soluble sugars were generally more abundant in leaves and nodules under elevated CO2, while starch and pinitol were depleted, indicating that additional photosynthates were rapidly used, in particular for nodule growth (dry mass increased by 65%). Ureides (allantoin and allantoic acid) increased under elevated CO2 in leaves, while this increase was not significant in nodules. The indigenous strain 12NS14 induced the highest ureides concentration in nodules under elevated CO2 along with the highest nitrogenase activity and increase in shoot dry mass, indicating a positive-feedback stimulation: soybean mobilized energy reserves to support more nodules, and in return nodules synthesized more ureides to support plant growth. In contrast, the commercial strain 532c resulted in the highest ureide concentrations in leaves, coupled with the lowest nitrogenase activity and nodules yield, suggesting a feedback inhibition of nodule activity. Our results show that selection of B. japonicum strains better adapted to elevated CO2 could improve soybean performance.

Selection of highly effective rectification regimes for ethyl alcohol

2006 ◽  
Vol 42 (9-10) ◽  
pp. 494-502
Author(s):  
N. A. Vyaz’mina ◽  
D. A. Baranov
Keyword(s):  
Ethyl Alcohol ◽  
Highly Effective ◽  
Selection Of

scholarly journals Evolving social behaviour through selection of single-cell adhesion in Dictyostelium discoideum

2021 ◽  
Author(s):  
Sandrine Adiba ◽  
Mathieu Forget ◽  
Silvia De Monte
Keyword(s):  
Cell Adhesion ◽  
Dictyostelium Discoideum ◽  
Experimental Evolution ◽  
Social Behaviour ◽  
Social Performance ◽  
Fruiting Bodies ◽  
Social Success ◽  
The Social ◽  
Different Strains ◽  
Selection Of

The social amoeba Dictyostelium discoideum commonly forms chimeric fruiting bodies by aggregation of different strains. Genetic variants that produce a higher proportion of spores are predicted to undercut multicellular organization unless cooperators assort positively. Cell adhesion is considered a primary factor driving such assortment, but evolution of adhesion has not been experimentally connected to changes in social performance. In this study we modified by experimental evolution the properties of individual cells, selecting for higher and lower adhesion to substrate. We then quantified the effects of these changes on cell-cell adhesion, development, and social behaviour. Unlike strains selected based on relative reproductive success in the social stage, we found that in binary chimeras both derived strains produce a smaller fraction of spores than the ancestor. Thus, evolution appears to have produced social cooperators. Examination of development revealed that this is however achieved via two opposed paths. Cells selected to be more adhesive to the substrate disproportionately contribute to the structural stability of fruiting bodies, as one would expect for cooperators. On the contrary, less adhesive cells behave as cheaters that undermine their own success more than that of the ancestor. These differences are reflected by a metric for social success that generalizes the classically used variation in frequency during the multicellular phase. Our work shows that cell mechanical interactions can constrain evolution of development and assortment in chimeras, and calls for integrating cell-level processes in conceptualizing the emergence of multicellular organization.

scholarly journals Selection of Resistant Streptococcus pneumoniae during Penicillin Treatment In Vitro and in Three Animal Models

2003 ◽  
Vol 47 (8) ◽  
pp. 2499-2506 ◽  
Author(s):  
Jenny Dahl Knudsen ◽  
Inga Odenholt ◽  
Helga Erlendsdottir ◽  
Magnus Gottfredsson ◽  
Otto Cars ◽  
...  
Keyword(s):  
Animal Models ◽  
Mixed Culture ◽  
Observation Time ◽  
Treatment Regimens ◽  
Rabbit Tissue ◽  
Drug Concentrations ◽  
Wide Range ◽  
Different Strains ◽  
Selection Of

ABSTRACT Pharmacokinetic (PK) and pharmacodynamic (PD) properties for the selection of resistant pneumococci were studied by using three strains of the same serotype (6B) for mixed-culture infection in time-kill experiments in vitro and in three different animal models, the mouse peritonitis, the mouse thigh, and the rabbit tissue cage models. Treatment regimens with penicillin were designed to give a wide range of T>MICs, the amounts of time for which the drug concentrations in serum were above the MIC. The mixed culture of the three pneumococcal strains, 107 CFU of strain A (MIC of penicillin, 0.016 μg/ml; erythromycin resistant)/ml, 106 CFU of strain B (MIC of penicillin, 0.25 μg/ml)/ml, and 105 CFU of strain C (MIC of penicillin, 4 μg/ml)/ml, was used in the two mouse models, and a mixture of 105 CFU of strain A/ml, 104 CFU of strain B/ml, and 103 CFU of strain C/ml was used in the rabbit tissue cage model. During the different treatment regimens, the differences in numbers of CFU between treated and control animals were calculated to measure the efficacies of the regimens. Selective media with erythromycin or different penicillin concentrations were used to quantify the strains separately. The efficacies of penicillin in vitro were similar when individual strains or mixed cultures were studied. The eradication of the bacteria, independent of the susceptibility of the strain or strains or the presence of the strains in a mixture or on their own, followed the well-known PK and PD rules for treatment with β-lactams: a maximum efficacy was seen when the T>MIC was >40 to 50% of the observation time and the ratio of the maximum concentration of the drug in serum to the MIC was >10. It was possible in all three models to select for the less-susceptible strains by using insufficient treatments. In the rabbit tissue cage model, a regrowth of pneumococci was observed; in the mouse thigh model, the ratio between the different strains changed in favor of the less-susceptible strains; and in the mouse peritonitis model, the susceptible strain disappeared and was overgrown by the less-susceptible strains. These findings with the experimental infection models confirm the importance of eradicating all the bacteria taking part in the infectious process in order to avoid selection of resistant clones.

scholarly journals Biological and Biochemical Characteristics of Cytoadhesion of Plasmodium falciparum-Infected Erythrocytes to Chondroitin-4-Sulfate

1998 ◽  
Vol 66 (10) ◽  
pp. 4950-4956 ◽  
Author(s):  
Bruno Pouvelle ◽  
Thierry Fusaï ◽  
Catherine Lépolard ◽  
Jürg Gysin
Keyword(s):  
Endothelial Cells ◽  
Plasmodium Falciparum ◽  
Minimum Size ◽  
Intercellular Adhesion Molecule ◽  
Intercellular Adhesion Molecule 1 ◽  
Prevalence Studies ◽  
Acidic Conditions ◽  
Different Strains ◽  
Selection Of

ABSTRACT The cytoadhesion of Plasmodium falciparum laboratory strains and clones to Saimiri brain microvascular endothelial cells (SBEC 17), with chondroitin-4-sulfate (CSA) as the only adhesion receptor, was tested. Only one strain had significant cytoadhesion. However, CSA-specific infected erythrocytes (IRBCs) were detected in all strains after selection of a CSA-specific subpopulation by culturing the few adherent IRBCs. This demonstrates the lack of sensitivity of cytoadhesion microassays for detecting small quantities of CSA-specific IRBCs in cultures or field isolates. Cytoadhesion to CSA is maximal at 24 h of the cycle and decreases with the onset of schizogony, reaching a minimum just before reinvasion. This fluctuation must be taken into account in comparisons of the cytoadhesion of different strains or isolates. The minimum size of CSA for active inhibition was 4 kDa, and a mass of 9 kDa was required for inhibition similar to that obtained with the 50-kDa CSA. In contrast to cytoadhesion to CSA, which is pH independent or maximal at physiological pH (depending on the target endothelial cells), adhesion to CD36 and intercellular adhesion molecule 1 was pH dependent, requiring acidic conditions to be maximal in all cases. Cytoadhesion to CSA may trigger the occlusion of microvessels and cause the acidosis necessary for the other receptors to be fully efficient. If this key role in the mechanisms of sequestration were to be confirmed in vivo, prevalence studies of the CSA cytoadhesion phenotype would have to be reevaluated, because simple cytoadhesion assays do not detect CSA-specific parasites present in very low numbers, and these parasites might then be undetected in the peripheral blood but present in organs in which sequestration occurs, such as the placenta (M. Fried and P. E. Duffy, Science 272:1502–1504, 1996).

Selection of Different Strains of Plasmodium falciparum for Testing Blood-Stage Vaccines in Aotus Nancymai Monkeys

1994 ◽  
Vol 51 (2) ◽  
pp. 224-232 ◽  
Author(s):  
William E. Collins ◽  
G. Gale Galland ◽  
Joann S. Sullivan ◽  
Carla L. Morris
Keyword(s):  
Plasmodium Falciparum ◽  
Blood Stage ◽  
Different Strains ◽  
Selection Of

scholarly journals Comparative Staging of Blastoderm Development at Oviposition in Eggs from Layer and Broiler Grandparent Breeder Flocks

2021 ◽  
Vol 9 (6) ◽  
pp. 1232-1236
Author(s):  
Serdar Özlü
Keyword(s):  
Egg Production ◽  
Pearson Correlation ◽  
Genetic Selection ◽  
Egg Weight ◽  
Layer Chicken ◽  
Significant Difference ◽  
The Mean ◽  
Hatching Eggs ◽  
Different Strains ◽  
Selection Of

Recent decades were characterized by genetic selection of broiler and layer chickens for enhanced growth rate and meat yield or intensified egg production, respectively. It is to be expected that genetic selection for various traits would also influence embryo development. The effects of different strains of chickens on egg weight, stage of blastoderm, variation of the blastoderm development and Pearson correlation between egg weight and stage of blastoderm at oviposition were studied in the current study. Hatching eggs were randomly collected from three layer chicken lines (Layer-1, Layer-2, and Layer-3) raised in Poultry Research Institute, and two broiler grandparent flocks (Female and Male) from Aviagen Anadolu. The age of all chicken lines was 36 week. A total of 30 eggs in each line were used, and egg weight and the blastoderm development of the embryos were determined at oviposition time. At the end of the research, significant difference in egg weights (P0.05). The mean stage of blastoderm development in male grandparent line eggs significantly lower than other four genetic lines (P

scholarly journals Behavior and Target Site Selection of Conjugative Transposon Tn916in Two Different Strains of Toxigenic Clostridium difficile

2012 ◽  
Vol 78 (7) ◽  
pp. 2147-2153 ◽  
Author(s):  
Peter Mullany ◽  
Rachel Williams ◽  
Gemma C. Langridge ◽  
Daniel J. Turner ◽  
Rachael Whalan ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Consensus Sequence ◽  
Conjugative Transposon ◽  
Content Type ◽  
Target Site Selection ◽  
Flagellar Biosynthesis ◽  
Intergenic Regions ◽  
High Throughput Dna Sequencing ◽  
Different Strains ◽  
Selection Of

ABSTRACTThe insertion sites of the conjugative transposon Tn916in the anaerobic pathogenClostridium difficilewere determined using Illumina Solexa high-throughput DNA sequencing of Tn916insertion libraries in two different clinical isolates: 630ΔE, an erythromycin-sensitive derivative of 630 (ribotype 012), and the ribotype 027 isolate R20291, which was responsible for a severe outbreak ofC. difficiledisease. A consensus 15-bp Tn916insertion sequence was identified which was similar in both strains, although an extended consensus sequence was observed in R20291. A search of theC. difficile630 genome showed that the Tn916insertion motif was present 100,987 times, with approximately 63,000 of these motifs located in genes and 35,000 in intergenic regions. To test the usefulness of Tn916as a mutagen, a functional screen allowed the isolation of a mutant. This mutant contained Tn916inserted into a gene involved in flagellar biosynthesis.

scholarly journals CULTIVATION OF BORDETELLA PERTUSSIS BIOFILMS ON ABIOTIC SUBSTRATE

2019 ◽  
Vol 1 (1) ◽  
pp. 49-53 ◽  
Author(s):  
E. M. Zaytsev ◽  
M. V. Britsina ◽  
M. N. Ozeretskovskaya ◽  
N. U. Mertsalova ◽  
I. G. Bazhanova
Keyword(s):  
Bordetella Pertussis ◽  
Nutrient Medium ◽  
Gentian Violet ◽  
Comparative Assessment ◽  
Original Strain ◽  
High Ability ◽  
Optimal Conditions ◽  
High Virulence ◽  
Different Strains ◽  
Selection Of

Aim. Selection of optimal conditions for the cultivation of Bordetella pertussis biofilms and comparative assessment of the ability of different strains to form biofilms. Materials and methods. Used a vaccine strain of B. pertussis № 475 and selected from this strain strain № 475а, characterized by high virulence. Cultures of strains grown on dense nutrient medium (DNM) and liquid nutrient medium (LNM) were used as inoculates for biofilms production. The intensity of biofilms formation in round-bottom 96-well polystyrene plates was estimated by staining with 0,1% gentian-violet solution. Results. Daily cultures of the strain № 475 with LNM formed moderate biofilms in the range of doses 5 — 1,25 IOU (international optical units) /ml, in the absence of growth at lower doses. The daily cultures of this strain with the DNM formed a dense biofilms when planting a doses in the range from 10 to 1,25 IOU/ml, moderate from 0,625 to 0,157 IOU/ml and weak biofilms at a dose of 0,079 IOU/ml. Strain № 475а with the DNM formed dense biofilms in the doses range of 10 to 0,04 IOU/ml and only at the dose of 0,02 IOU/ml were formed moderate biofilms. Conclusion. A simple and informative method has been developed to evaluate the ability of B. pertussis strains to form biofilms in polystyrene plates. Cultures obtained with the DNM formed a more significant biofilms than cultures with LNM. Identified high ability to biofilms formation by a selected strain №. 475a, compared to the original strain № 475.

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