scholarly journals Heterogeneous A40926 Self-Resistance Profile in Nonomuraea gerenzanensis Population Informs Strain Improvement

Fermentation ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 140
Author(s):  
Elisa Binda ◽  
Francesca Berini ◽  
Flavia Marinelli ◽  
Adriana Bava ◽  
Fabrizio Beltrametti
Keyword(s):  
Population Analysis ◽  
Strain Improvement ◽  
Glycopeptide Antibiotic ◽  
Wild Type ◽  
Resistant Population ◽  
Type Population ◽  
The Cost ◽  
Slow Growing ◽  
Natural Precursor ◽  
Selection Of

Nonomuraea gerenzanensis ATCC 39727 produces the glycopeptide antibiotic A40926, which is the natural precursor of the semi-synthetic, last-resort drug dalbavancin. To reduce the cost of dalbavancin production, it is mandatory to improve the productivity of the producing strain. Here, we report that the exposure of N. gerenzanensis wild-type population to sub-inhibitory concentrations of A40926 led to the isolation of differently resistant phenotypes to which a diverse A40926 productivity was associated. The most resistant population (G, grand colonies) represented at least the 20% of the colonies growing on 2 µg/mL of A40926. It showed a stable phenotype after sub-culturing and a homogeneous profile of self-resistance to A40926 in population analysis profile (PAP) experiments. The less resistant population (P, petit) was represented by slow-growing colonies to which a lower A40926 productivity was associated. At bioreactor scale, the G variant produced twice more than the wild-type (ca. 400 mg/L A40926 versus less than 200 mg/L, respectively), paving the way for a rational strain improvement based on the selection of increasingly self-resistant colonies.

In vivo selection of a population of Trypanosoma cruzi and clones resistant to benznidazole

Parasitology ◽  
1998 ◽  
Vol 116 (2) ◽  
pp. 165-171 ◽  
Author(s):  
S. M. F. MURTA ◽  
A. J. ROMANHA
Keyword(s):  
Mortality Rate ◽  
Trypanosoma Cruzi ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type ◽  
Long Term Treatment ◽  
Resistant Population ◽  
Parasitaemia Level ◽  
Selection Of

A benznidazole-resistant population of Trypanosoma cruzi, Y strain, was selected after 25 successive passages (8 months) in mice treated with a single high drug dose. Initially, the resistant parasites produced a low parasitaemia level and low mortality rate in infected mice. Thereafter, the parasitaemia level and mortality rate increased to the same value obtained for mice infected with the wild-type strain. Long-term treatment with benznidazole (100 mg/kg/day) cured 71–80% of mice infected with the wild-type strain. No cure was observed in mice infected with the selected resistant parasite population. Treatment with 500 mg/kg of benznidazole at peak parasitaemia cleared all blood parasites from mice infected with wild-type parasites. No effect on parasitaemia level was observed in mice infected with the selected parasites. Benznidazole-resistant parasites showed cross-resistance to different drugs. Contrary to wild type, all clones analysed from the resistant T. cruzi population were resistant to benznidazole. Without drug pressure the resistance phenotype of clones was far more stable than that presented by the resistant population. This work demonstrates, for the first time, the in vivo selection of a population and clones of T. cruzi resistant to benznidazole, and makes available an experimental model for the study of mechanisms of drug resistance in T. cruzi.

scholarly journals Escherichia coli mutators: selection criteria and migration effect

Microbiology ◽  
2006 ◽  
Vol 152 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Ludovic Le Chat ◽  
Michel Fons ◽  
Francois Taddei
Keyword(s):  
Adaptive Mutation ◽  
Wild Type ◽  
Adaptive Mutations ◽  
Migration Effect ◽  
Frequency Independent ◽  
Type Population ◽  
And Migration ◽  
Selection Of

In silico, it has been shown that mutator alleles that increase mutation rate can be selected for by generating adaptive mutations. In vitro and in vivo, competition between wild-type bacteria and isogenic mutator mutants is consistent with this view. However, in vivo, the gain of the mutator seems to be reduced when migration is allowed. In vitro, the advantage of mutators has been described as frequency-dependent, leading to mutator advantage only when they are sufficiently frequent. Using an in vitro system, it is demonstrated that (i) the selection of mutators is frequency-independent, yet depends on at least one mutator bacterium bearing an adaptive mutation (its presence depends on chance, mutation rates and population size of mutator bacteria); (ii) on average, the mutator gain is always equal to the ratio of the adaptive mutation frequency of the mutator versus wild-type; (iii) when migration into an empty niche is allowed, the mutator benefit is reduced if migration occurs after fixation of the adaptive mutation into the wild-type population. It is concluded that in all cases, mutator gain depends directly on the ratio of bacteria carrying a beneficial mutation in mutator versus wild-type lineages.

scholarly journals Selection of Populations of Puccinia recondita f. sp. tritici for Shortened Latent Period on a Partially Resistant Wheat Cultivar

1997 ◽  
Vol 87 (2) ◽  
pp. 170-176 ◽  
Author(s):  
Jeffrey S. Lehman ◽  
Gregory Shaner
Keyword(s):  
Growth Rate ◽  
Latent Period ◽  
Puccinia Recondita ◽  
Infection Frequency ◽  
Wheat Cultivars ◽  
Wild Type ◽  
Parasitic Fitness ◽  
Fungal Populations ◽  
Type Population ◽  
Selection Of

Wild-type fungal population 851-WT was selected for shortened latent period on cv. CI 13227 for five uredinial generations to study the adaptation of Puccinia recondita f. sp. tritici to partially resistant wheat cultivars. Differences among wild-type and selected populations for traits contributing to parasitic fitness (i.e., latent period, infection frequency, and uredinium area and growth rate) were assessed in monocyclic infection experiments on susceptible cv. Monon and partially resistant cvs. Suwon 85, Sw 72469-6, L-574-1, and CI 13227. Differences were greatest among fungal populations on cv. CI 13227. The mean latent period of selected population 851-C5 was 2 days shorter (~20%) than that of wild-type population 851-WT. In addition, uredinia of population 851-C5 expanded 40% faster and produced ~75% more urediniospores. On cv. L-574-1, the selected population was also more fit than the wild-type progenitor for initial uredinium area and growth rate and cumulative urediniospore production. In contrast to wild-type and selected populations on cvs. CI 13227 and L-574-1, selected population 851-C5 on cv. Monon produced slower expanding uredinia with fewer urediniospores than did population 851-WT on Monon. These results show that variation in the latent period of P. recondita f. sp. tritici populations is partially under genetic control and wild-type P. recondita f. sp. tritici populations contain members reproductively more fit on partially resistant wheat cultivars but not necessarily on susceptible cultivars. Such members are capable of partially overcoming quantitative host resistance.

Determination of the minimum number of technological bases of a part

2020 ◽  
pp. 73-75
Author(s):  
B.M. Bazrov ◽  
T.M. Gaynutdinov
Keyword(s):  
Cost Price ◽  
Labor Input ◽  
Part Surface ◽  
Technological Base ◽  
Size Accuracy ◽  
Minimum Number ◽  
The Cost ◽  
Input Cost ◽  
Selection Of

The selection of technological bases is considered before the choice of the type of billet and the development of the route of the technological process. A technique is proposed for selecting the minimum number of sets of technological bases according to the criterion of equality in the cost price of manufacturing the part according to the principle of unity and combination of bases at this stage. Keywords: part, surface, coordinating size, accuracy, design and technological base, labor input, cost price. [email protected]

scholarly journals Putative transmembrane transporter modulates higher-level aggression in Drosophila

2017 ◽  
Vol 114 (9) ◽  
pp. 2373-2378 ◽  
Author(s):  
Budhaditya Chowdhury ◽  
Yick-Bun Chan ◽  
Edward A. Kravitz
Keyword(s):  
Causal Effect ◽  
Nerve Terminals ◽  
Rna Seq ◽  
Wild Type ◽  
Temperature Dependent ◽  
Number Of Genes ◽  
Interesting Family ◽  
Solute Carrier ◽  
Transmembrane Transporter ◽  
Selection Of

By selection of winners of dyadic fights for 35 generations, we have generated a hyperaggressive Bully line of flies that almost always win fights against the parental wild-type Canton-S stock. Maintenance of the Bully phenotype is temperature dependent during development, with the phenotype lost when flies are reared at 19 °C. No similar effect is seen with the parent line. This difference allowed us to carry out RNA-seq experiments and identify a limited number of genes that are differentially expressed by twofold or greater in the Bullies; one of these was a putative transmembrane transporter, CG13646, which showed consistent and reproducible twofold down-regulation in Bullies. We examined the causal effect of this gene on the phenotype with a mutant line for CG13646, and with an RNAi approach. In all cases, reduction in expression of CG13646 by approximately half led to a hyperaggressive phenotype partially resembling that seen in the Bully flies. This gene is a member of a very interesting family of solute carrier proteins (SLCs), some of which have been suggested as being involved in glutamine/glutamate and GABA cycles of metabolism in excitatory and inhibitory nerve terminals in mammalian systems.

scholarly journals A microfluidic device enabling drug resistance analysis of leukemia cells via coupled dielectrophoretic detection and impedimetric counting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yağmur Demircan Yalçın ◽  
Taylan Berkin Töral ◽  
Sertan Sukas ◽  
Ender Yıldırım ◽  
Özge Zorlu ◽  
...  
Keyword(s):  
Drug Resistance ◽  
K562 Cells ◽  
Leukemia Cells ◽  
Drug Resistant ◽  
Wild Type ◽  
Gene Expressions ◽  
Before And After ◽  
The Difference ◽  
Selection Of ◽  
Resistant Cells

AbstractWe report the development of a lab-on-a-chip system, that facilitates coupled dielectrophoretic detection (DEP-D) and impedimetric counting (IM-C), for investigating drug resistance in K562 and CCRF-CEM leukemia cells without (immuno) labeling. Two IM-C units were placed upstream and downstream of the DEP-D unit for enumeration, respectively, before and after the cells were treated in DEP-D unit, where the difference in cell count gave the total number of trapped cells based on their DEP characteristics. Conductivity of the running buffer was matched the conductivity of cytoplasm of wild type K562 and CCRF-CEM cells. Results showed that DEP responses of drug resistant and wild type K562 cells were statistically discriminative (at p = 0.05 level) at 200 mS/m buffer conductivity and at 8.6 MHz working frequency of DEP-D unit. For CCRF-CEM cells, conductivity and frequency values were 160 mS/m and 6.2 MHz, respectively. Our approach enabled discrimination of resistant cells in a group by setting up a threshold provided by the conductivity of running buffer. Subsequent selection of drug resistant cells can be applied to investigate variations in gene expressions and occurrence of mutations related to drug resistance.

scholarly journals The Recent Progress of Natural Sources and Manufacturing Process of Biodiesel: A Review

2021 ◽  
Vol 13 (10) ◽  
pp. 5599
Author(s):  
Eko Supriyanto ◽  
Jayan Sentanuhady ◽  
Ariyana Dwiputra ◽  
Ari Permana ◽  
Muhammad Akhsin Muflikhun
Keyword(s):  
Recent Progress ◽  
Review Paper ◽  
Ghg Emissions ◽  
Production Method ◽  
Biodiesel Production ◽  
Natural Sources ◽  
Harmful Emissions ◽  
Daily Energy ◽  
The Cost ◽  
Selection Of

Biodiesel has caught the attention of many researchers because it has great potential to be a sustainable fossil fuel substitute. Biodiesel has a non-toxic and renewable nature and has been proven to emit less environmentally harmful emissions such as hydrocarbons (HC), and carbon monoxide (CO) as smoke particles during combustion. Problems related to global warming caused by greenhouse gas (GHG) emissions could also be solved by utilizing biodiesel as a daily energy source. However, the expensive cost of biodiesel production, mainly because of the cost of natural feedstock, hinders the potential of biodiesel commercialization. The selection of natural sources of biodiesel should be made with observations from economic, agricultural, and technical perspectives to obtain one feasible biodiesel with superior characteristics. This review paper presents a detailed overview of various natural sources, their physicochemical properties, the performance, emission, and combustion characteristics of biodiesel when used in a diesel engine. The recent progress in studies about natural feedstocks and manufacturing methods used in biodiesel production were evaluated in detail. Finally, the findings of the present work reveal that transesterification is currently the most superior and commonly used biodiesel production method compared to other methods available.

Recruitment and selection of couples for intervention research: Achieving developmental homogeneity at the cost of demographic diversity.

2006 ◽  
Vol 74 (4) ◽  
pp. 777-784 ◽  
Author(s):  
Ronald D. Rogge ◽  
Rebecca J. Cobb ◽  
Lisa B. Story ◽  
Matthew D. Johnson ◽  
Erika E. Lawrence ◽  
...  
Keyword(s):  
Intervention Research ◽  
Demographic Diversity ◽  
Recruitment And Selection ◽  
The Cost ◽  
Selection Of

Construction of Temporary Accommodation Camp and Selection of Optimal Type of Building

2015 ◽  
Vol 725-726 ◽  
pp. 105-110
Author(s):  
Aleksandr Birjukov ◽  
Sergey Bolotin
Keyword(s):  
Type Systems ◽  
Structural Systems ◽  
Basic Criterion ◽  
Economic Indexes ◽  
The Cost ◽  
Container Type ◽  
Selection Of ◽  
Optimal Type ◽  
Temporary Accommodation

Surveys performed nationwide show that mobile temporary accommodation camps are being manufactured by more than 200 specialized enterprises (without considering the minor manufacturers) acting under different ministries and agencies. According to the analysis performed, today 26 basic mobile structural systems consisting of 18 conveyor-type and 8 demountable-type systems are being used on a national basis. Today national manufacturers are producing more than 250 types of container-type buildings and facilities which differ in functionality, capacity, climatic category, price and other technical-and-economic indexes. Use of mobile accommodation complexes is characterized by certain advantages. Basic criterion for mobile accommodation camp construction consists in its timely commissioning. Basic predicted indexes affecting the cost of temporary accommodation camp could serve as an endorsement of the forwarded standpoint.

The Use of SGLT2i and GLP-1 RA in Patients with Type 2 Diabetes in Thailand: Evidence Review and Recommendations

2021 ◽  
Vol 104 (11) ◽  
pp. 1850-1865
Keyword(s):  
Type 2 Diabetes ◽  
Glucose Lowering ◽  
Sodium Glucose Cotransporter ◽  
Evidence Review ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Glucose Lowering Therapy ◽  
The Cost ◽  
Selection Of

Background: Cardiovascular (CV) and renal comorbidities are common among type 2 diabetes (T2D) patients, and significantly increase the cost and burden of care. Both sodium-glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1 RA) improve key outcomes including major CV events, hospitalization for heart failure, and renal outcomes, albeit to varying degrees in different T2D populations. Materials and Methods: The authors reviewed evidence from GLP-1 RA and SGLT2i CV outcomes trials and real-world studies in Thailand and elsewhere. Results: The authors formulated recommendations to guide selection of anti-diabetes medication based on patients’ clinical characteristics and CV or renal risk profile. Conclusion: These recommendations could help guide management of CV/renal comorbidities and risk alongside glucose-lowering therapy for individual patients. Keywords: Type 2 diabetes mellitus; Cardiovascular diseases; Chronic kidney disease; Clinical outcomes; SGLT2i; GLP-1 RA

Sign in / Sign up

Export Citation Format

Share Document