Timing of the G1/S transition in tobacco pollen vegetative cells as a primary step towards androgenesis in vitro

2014 ◽  
Vol 33 (9) ◽  
pp. 1595-1606 ◽  
Author(s):  
Masaharu Kyo ◽  
Ai Nagano ◽  
Naoki Yamaji ◽  
Yuhki Hashimoto
Keyword(s):  
Vegetative Cells ◽  
Tobacco Pollen ◽  
Androgenesis In Vitro

Control of the developmental pathway of tobacco pollen in vitro

Planta ◽  
1986 ◽  
Vol 168 (4) ◽  
pp. 427-432 ◽  
Author(s):  
M. Kyo ◽  
H. Harada
Keyword(s):  
Developmental Pathway ◽  
Tobacco Pollen

Morphology of Cell Injury: An Approach to the EDIT Programme by the Use of Tobacco Pollen Tubes

2002 ◽  
Vol 30 (3) ◽  
pp. 323-329 ◽  
Author(s):  
Udo Kristen ◽  
Natalie Bischoff ◽  
Saskia Lisboa ◽  
Enno Schirmer ◽  
Sören Witt ◽  
...  
Keyword(s):  
Tip Growth ◽  
Cell Injury ◽  
Cytosolic Calcium ◽  
Pollen Tubes ◽  
In Vitro Cytotoxicity ◽  
Toxic Compounds ◽  
In Vitro System ◽  
Tobacco Pollen ◽  
Different Types

Tobacco pollen tubes were used as a standard in vitro system to investigate cell growth aberrations caused by some of the Multicentre Evaluation of In Vitro Cytotoxicity (MEIC) programme chemicals and other toxic compounds. Changes in cytoskeletal pattern were observed in the tube cells by using tubu-lin immunofluorescence and rhodamin–phalloidin fluorescence for the localisation of microtubules and actin filaments, respectively. Four different types of cell malformation were found: screw-like growth, isodiametric tip swelling, hook formation, and pollen grain enlargement. We suggest that these malformations resulted from an interference by the chemicals with the cytosolic calcium gradient which controls tip growth and the orientation of the pollen tube. The results may contribute to a general understanding of toxicity-based cell malformations.

scholarly journals Efficiency of using different types induction culture medium for hexaploid triticale anther cultivation

2019 ◽  
Vol 25 ◽  
pp. 260-265
Author(s):  
E. V. Lagunovskaya ◽  
O. I. Zaitseva ◽  
V. A. Lemesh
Keyword(s):  
Culture Medium ◽  
Medium Composition ◽  
Induction Medium ◽  
Hexaploid Triticale ◽  
Culture Methods ◽  
Study Results ◽  
Short Period ◽  
Androgenesis In Vitro ◽  
The Republic

Aim. Triticale is one of the main grain crops of the Republic of Belarus. Further progress in the selection of this culture involves the accelerated creation of highly productive early ripening varieties resistant to abiotic and biotic factors. The method of induced androgenesis in vitro makes it possible to obtain stable homozygous lines in a short period of time and to eliminate the lengthy process of inbreeding used in classical breeding to fix the desired traits. Methods. The tissue and cell culture methods for plants was used in the study. Results. The influence of the induction medium composition on the efficiency of in vitro induced androgenesis in varieties and lines of hexaploid triticale is assessed. The influence of three types of induction culture medium, the type of phytohormones and the presence or absence of cefotaxime in the medium are analyzed. Results. It has been shown that using the C-17 culture medium supplemented with 2.0 mg/l 2,4-D and 0.5 mg/l kinetin without adding cefotaxime is most effective for the anther triticale cultivation. Keywords: triticale, anther culture, induction nutrient medium, embryoids, calli, regenerant plants, cefotaxime.

scholarly journals Omadacycline compared to vancomycin when combined with germinants to disrupt the life cycle of Clostridioides difficile

2021 ◽  
Author(s):  
Noah Budi ◽  
Jared J. Godfrey ◽  
Nasia Safdar ◽  
Sanjay K. Shukla ◽  
Warren E. Rose
Keyword(s):  
Limit Of Detection ◽  
Disease Relapse ◽  
Vegetative Cells ◽  
Spore Form ◽  
Safety And Efficacy ◽  
Healthcare Environment ◽  
Clostridioides Difficile ◽  
Spore Shedding ◽  
Dormant Spore

Clostridioides difficile (C. difficile) infections (CDI) are commonly treated with antibiotics that do not impact the dormant spore form of the pathogen. CDI-directed antibiotics, such as vancomycin and metronidazole, can destroy the vegetative form of C. difficile and protective microbiota. After treatment, spores can germinate into vegetative cells causing clinical disease relapse and further spore shedding. This in vitro study compares the combination of germinants with vancomycin or omadacycline to antibiotics alone in eradicating C. difficile spores and vegetative cells. Among the four strains in this study, omadacycline minimum inhibitory concentrations (0.031-0.125 mg/L) were lower than vancomycin (1-4 mg/L). Omadacycline nor vancomycin in media alone reduced spore counts. In three of the four strains, including the epidemic ribotype 027, spore eradication with germinants was 94.8-97.4% with vancomycin and 99.4-99.8% with omadacycline (p<0.005). In ribotype 012, either antibiotic combined with germinants resulted in 100% spore eradication at 24 hours. The addition of germinants with either antibiotic did not result in significant toxin A or B production, which were below the limit of detection (<1.25 ng/mL) by 48 hours. Limiting the number of spores present in patient GI tracts at the end of therapy may be effective at preventing recurrent CDI and limiting spore shedding in the healthcare environment. These results with germinants warrant safety and efficacy evaluations in animal models.

scholarly journals How the Anaerobic Enteropathogen Clostridioides difficile Tolerates Low O2 Tensions

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Nicolas Kint ◽  
Carolina Alves Feliciano ◽  
Maria C. Martins ◽  
Claire Morvan ◽  
Susana F. Fernandes ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Anaerobic Bacteria ◽  
Growth Defect ◽  
Strictly Anaerobic ◽  
Low Oxygen ◽  
Air Exposure ◽  
Vegetative Cells ◽  
Content Type ◽  
Clostridioides Difficile

ABSTRACT Clostridioides difficile is a major cause of diarrhea associated with antibiotherapy. After germination of C. difficile spores in the small intestine, vegetative cells are exposed to low oxygen (O2) tensions. While considered strictly anaerobic, C. difficile is able to grow in nonstrict anaerobic conditions (1 to 3% O2) and tolerates brief air exposure indicating that this bacterium harbors an arsenal of proteins involved in O2 detoxification and/or protection. Tolerance of C. difficile to low O2 tensions requires the presence of the alternative sigma factor, σB, involved in the general stress response. Among the genes positively controlled by σB, four encode proteins likely involved in O2 detoxification: two flavodiiron proteins (FdpA and FdpF) and two reverse rubrerythrins (revRbr1 and revRbr2). As previously observed for FdpF, we showed that both purified revRbr1 and revRbr2 harbor NADH-linked O2- and H2O2-reductase activities in vitro, while purified FdpA mainly acts as an O2-reductase. The growth of a fdpA mutant is affected at 0.4% O2, while inactivation of both revRbrs leads to a growth defect above 0.1% O2. O2-reductase activities of these different proteins are additive since the quadruple mutant displays a stronger phenotype when exposed to low O2 tensions compared to the triple mutants. Our results demonstrate a key role for revRbrs, FdpF, and FdpA proteins in the ability of C. difficile to grow in the presence of physiological O2 tensions such as those encountered in the colon. IMPORTANCE Although the gastrointestinal tract is regarded as mainly anoxic, low O2 tension is present in the gut and tends to increase following antibiotic-induced disruption of the host microbiota. Two decreasing O2 gradients are observed, a longitudinal one from the small to the large intestine and a second one from the intestinal epithelium toward the colon lumen. Thus, O2 concentration fluctuations within the gastrointestinal tract are a challenge for anaerobic bacteria such as C. difficile. This enteropathogen has developed efficient strategies to detoxify O2. In this work, we identified reverse rubrerythrins and flavodiiron proteins as key actors for O2 tolerance in C. difficile. These enzymes are responsible for the reduction of O2 protecting C. difficile vegetative cells from associated damages. Original and complex detoxification pathways involving O2-reductases are crucial in the ability of C. difficile to tolerate O2 and survive to O2 concentrations encountered in the gastrointestinal tract.

Comparison of the plant growth-promotion performance of a consortium of Bacilli inoculated as endospores or as vegetative cells

2019 ◽  
Vol 95 (11) ◽  
Author(s):  
Isha Hashmi ◽  
Christophe Paul ◽  
Andrej Al-Dourobi ◽  
Frederic Sandoz ◽  
Priscilla Deschamps ◽  
...  
Keyword(s):  
Seed Germination ◽  
Plant Growth ◽  
Positive Impact ◽  
Growth Promotion ◽  
Soil Microbial Communities ◽  
Vegetative Cells ◽  
Single Strain ◽  
Positive Effects ◽  
Pot Experiments

ABSTRACT The effect of three plant growth-promoting Bacillus strains inoculated either alone or as a consortium was tested on oat (Avena sativa) growth. The bioinoculants were applied as vegetative cells or endospores at low cell densities on the seeds and their effect was tested in sterile in vitro conditions, pot experiments, and a field trial. The in vitro seed germination assay showed that both individual bacterial inocula and bacterial consortia had positive effects on seed germination. Greenhouse pot experiments with sterile and non-sterile soil showed that consortia increased the total dry biomass of oat plants as compared to single strain inoculation and uninoculated controls. However, the positive impact on plant growth was less prominent when the bioinoculated strains had to compete with native soil microbes. Finally, the field experiment demonstrated that the consortium of vegetative cells was more efficient in promoting oat growth than the endospore consortium and the uninoculated control. Moreover, both consortia successfully colonized the roots and the rhizosphere of oat plants, without modifying the overall structure of the autochthonous soil microbial communities.

Survival of Bacillus cereus Vegetative Cells and Spores during In Vitro Simulation of Gastric Passage

2012 ◽  
Vol 75 (4) ◽  
pp. 690-694 ◽  
Author(s):  
SIELE CEUPPENS ◽  
MIEKE UYTTENDAELE ◽  
KATRIEN DRIESKENS ◽  
ANDREJA RAJKOVIC ◽  
NICO BOON ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Acid Resistance ◽  
In Vitro Experiments ◽  
Vegetative Cells ◽  
Ph Values ◽  
Constant Ph ◽  
In Vitro Simulation ◽  
Ph Range

The enteric pathogen Bacillus cereus must survive gastric passage in order to cause diarrhea by enterotoxin production in the small intestine. The acid resistance and the survival after gastric passage were assessed by in vitro experiments with acidified growth medium and gastric simulation medium with B. cereus NVH 1230-88 vegetative cells and spores. First, batch incubations at constant pH values for 4 h, which represented different physiological states of the stomach, showed that spores were resistant to any gastric condition in the pH range of 2.0 to 5.0, while vegetative cells were rapidly inactivated at pH values of ≤4.0. Second, a dynamic in vitro gastric experiment was conducted that simulated the continuously changing in vivo conditions due to digestion dynamics by gradually decreasing the pH from 5.0 to 2.0 and fractional emptying of the stomach 30 to 180 min from the start of the experiment. All of the B. cereus spores and 14% (±9%) of the vegetative cells survived the dynamic simulation of gastric passage.

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