scholarly journals Factors Affecting Seed Production in Transgenic Ethylene-insensitive Petunias

2004 ◽  
Vol 129 (3) ◽  
pp. 401-406 ◽  
Author(s):  
Donna J. Clevenger ◽  
James E. Barrett ◽  
Harry J. Klee ◽  
David G. Clark
Keyword(s):  
Seed Germination ◽  
Fruit Ripening ◽  
Seed Weight ◽  
Pollen Viability ◽  
Dry Mass ◽  
Effect Of Temperature ◽  
Flower Senescence ◽  
Paternal Effects ◽  
Factors Affecting

Pollen viability, in-vivo pollen tube growth, fruit ripening, seed germination, seed weight, whole plant vigor, and natural flower senescence were investigated in homozygous and heterozygous transgenic ethylene-insensitive CaMV35S::etr1-1 petunias (Petunia ×hybrida `Mitchell Diploid'). Homozygous or heterozygous plants were used to determine any maternal and/or paternal effects of the CaMV35S::etr1-1 transgene. All experiments except for those used to determine natural flower senescence characteristics were conducted in both high and low temperature greenhouses to determine the effect of temperature stress on transgenic plants when compared to wild-type. Results indicated that ethylene-insensitive plants had a decrease in pollen viability, root dry mass, seed weight, and seed germination. Fruit ripening, seed germination, and seed weight were maternally regulated. In contrast, the CaMV35S::etr1-1 transgene is completely dominant in its effect on natural flower senescence.

scholarly journals Effects of High Temperature on Embryological Development and Hormone Profile in Flowers and Leaves of Common Buckwheat (Fagopyrum esculentum Moench)

2019 ◽  
Vol 20 (7) ◽  
pp. 1705 ◽  
Author(s):  
Agnieszka Płażek ◽  
Aneta Słomka ◽  
Przemysław Kopeć ◽  
Michał Dziurka ◽  
Marta Hornyák ◽  
...  
Keyword(s):  
Thermal Stress ◽  
High Temperature ◽  
Developmental Stages ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Effect Of Temperature ◽  
Flower Senescence ◽  
Embryological Development ◽  
Common Buckwheat ◽  
Fagopyrum Esculentum Moench

Common buckwheat is a valuable crop, mainly due to the beneficial chemical composition of its seeds. However, buckwheat cultivation is limited because of unstable seed yield. The most important reasons for the low yield include embryo and flower abortion. The aim of this work is to verify whether high temperature affects embryological development in this plant species. The experiment was conducted on plants of a Polish cultivar ‘Panda’ and strain PA15, in which the percentage of degenerating embryo sacs was previously determined and amounted to 32% and 10%, respectively. The plants were cultivated in phytotronic conditions at 20 °C (control), and 30 °C (thermal stress). The embryological processes and hormonal profiles in flowers at various developmental stages (buds, open flowers, and wilted flowers) and in donor leaves were analyzed in two-month-old plants. Significant effects of thermal stress on the defective development of female gametophytes and hormone content in flowers and leaves were observed. Ovules were much more sensitive to high temperature than pollen grains in both genotypes. Pollen viability remained unaffected at 30 °C in both genotypes. The effect of temperature on female gametophyte development was visible in cv. Panda but not in PA15 buds. A drastic reduction in the number of properly developed embryo sacs was clear in open flowers at 30 °C in both genotypes. A considerable increase in abscisic acid in open flowers ready for fertilization may serve as a signal inducing flower senescence observed in the next few days. Based on embryological analyses and hormone profiles in flowers, we conclude that cv. ‘Panda’ is more sensitive to thermal stress than strain PA15, mainly due to a much earlier response to thermal stress involving impairment of embryological processes already in the flower buds.

scholarly journals Factors affecting germination of great bindweed (Calystegia silvatica) seeds

2019 ◽  
Vol 72 ◽  
pp. 147-152
Author(s):  
Kerry C. Harrington ◽  
Tracey L. Gawn ◽  
Cory Matthew ◽  
Hossein Ghanizadeh
Keyword(s):  
Seed Germination ◽  
Seed Banks ◽  
Effect Of Temperature ◽  
Dormancy Breaking ◽  
Factors Affecting ◽  
Hard Seed ◽  
Factors Influencing ◽  
Viable Seeds ◽  
Hard Seed Coat ◽  
Number Of Seeds

Great bindweed (Calystegia silvatica) invades riparian plantings in New Zealand but little is known about the factors influencing seed germination of this species, the number of seeds produced per flower or whether seed banks build up in the soil below infested sites. Dormancy-breaking treatments involving scarification and/or pre-chilling of seeds were evaluated. The effect of temperature on germination was also studied. The presence of viable seeds in capsules on vines and in the soil beneath established stands was quantified. Great bindweed seeds needed scarification but not a period of cold temperature to germinate. Germination occurred from 5oC to 25oC but germination was greater and more rapid at higher temperatures. Seed capsules contained an average of only 2.3 seeds, and the soil beneath plants had, on average, only 21.9 seeds/m2. Seeds were large with one thousand seeds weighing 43.4 g. Once the hard seed coat is broken, seeds will germinate readily at warmer times of the year, but seed production is not prolific so seeds might not be that important for spread of the species.

Factors Affecting Eclipta (Eclipta prostrata) Seed Germination

1996 ◽  
Vol 10 (4) ◽  
pp. 727-731 ◽  
Author(s):  
John V. Altom ◽  
Don S. Murray
Keyword(s):  
Seed Germination ◽  
Incubation Period ◽  
Effect Of Temperature ◽  
Distilled Water ◽  
Solution Ph ◽  
Factors Affecting ◽  
Water Potentials ◽  
Light Intensities ◽  
Eclipta Prostrata ◽  
Water Ph

Controlled environmental chamber experiments were conducted for a 14-d incubation period to measure the effect of temperature, light, light intensity, water potential, and pH on eclipta seed germination. In full light, seed germinated over a range of 10 to 35 C; however, germination was highest at 83% at 35 C. Seeds were strongly photoblastic with none germinating in the dark. Seeds germinated in light intensities between 6 and 100% of full light. Seeds germinated 78 to 88% in water potentials of 0.0, −0.1, and −0.2 MPa. In distilled water (pH ∼ 5.5) and a buffered solution pH 6 and 7, seeds germinated 85 to 89%; however, some seeds germinated in a buffered solution pH range of 5 to 8. After the first 14-d incubation period, ungerminated seeds were transferred to distilled water and incubated at 35 C in full light for 4 to 6 d as a second incubation period. Seeds germinated 89 to 96% after this second incubation period when first incubation was at temperatures 10 to 35 C in full light or darkness, light intensities 0 to 100% of full light, water potentials 0.0 to −0.8 MPa, and buffered solution pH levels of 5.5 to 7.

scholarly journals Seasonal-dependent effect of temperature on the response of adenylate cyclase to FSH stimulation in the oviparous lizard, Podarcis sicula

2000 ◽  
Vol 167 (2) ◽  
pp. 275-280 ◽  
Author(s):  
L Borrelli ◽  
R De Stasio ◽  
CM Motta ◽  
E Parisi ◽  
S Filosa
Keyword(s):  
Adenylate Cyclase ◽  
Environmental Parameters ◽  
Reproductive Period ◽  
Effect Of Temperature ◽  
Ovarian Activity ◽  
Podarcis Sicula ◽  
Oocyte Growth ◽  
Factors Affecting

The study of environmental factors affecting vertebrate reproduction has long interested both developmental and evolutionary biologists. Although photoperiod has been considered to be an important environmental parameter for vertebrates such as birds, temperature is probably a primary external factor responsible for reproductive cyclicity in reptiles. In spite of the progress made in the understanding of reptilian reproductive strategies and adaptations, much remains to be learned about the interplay between endocrine physiological factors, such as hormones, and environmental parameters. In this report, we have examined the effects of in vivo administered FSH on oocyte recruitment during the most significant periods of the reproductive cycle of the lizard, Podarcis sicula. The results show that when FSH is administered in proximity to the reproductive period, it stimulates oocyte growth and ovulation; when the hormone is administered at the beginning of the winter stasis it affects ovarian activity without inducing ovulation. Ovarian adenylate cyclase activity is moderately sensitive to in vitro FSH stimulation during the pre- and post-reproductive periods. The sensitivity to hormone stimulation increases significantly during the reproductive period and winter stasis. We have also tested the hypothesis that environmental temperature affects the responsiveness of ovarian adenylate cyclase to FSH stimulation. For such a purpose, we exposed animals to 28 degrees C or 4 degrees C in different periods of the ovarian cycle. The results show that, whenever the temperature applied mimics the thermal regime of the coming season, adenylate cyclase sensitivity to FSH shifts towards levels that anticipate the natural responsiveness.

scholarly journals EFFECT OF TEMPERATURE AND LIGHT ON SEED GERMINATION AND SEEDLING GROWTH OF Swietenia macrophylla King

2020 ◽  
Vol 33 (3) ◽  
pp. 728-734
Author(s):  
CLEVERSON AGUEIRO DE CARVALHO ◽  
JOSUÉ BISPO DA SILVA ◽  
CHARLINE ZARATIN ALVES ◽  
CLIMBIÊ FERREIRA HALL ◽  
MAYARA FÁVERO COTRIM ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seedling Growth ◽  
Physiological State ◽  
Dry Mass ◽  
Effect Of Temperature ◽  
Economic Potential ◽  
Swietenia Macrophylla ◽  
Germination Process ◽  
Native Populations ◽  
Adequate Evaluation

ABSTRACT The significant economic potential of Swietenia macrophylla has caused immense reductions in the native populations, jeopardizing their survival. Restoring these populations requires the establishment of quality seedling production, which depends on adequate evaluation of the physiological state of seeds. Thus, the aim of this study was to evaluate the effect of temperature and light on seed germination and seedling growth of S. macrophylla. The experimental design was completely randomized, with ten treatments of four replicates of 50 seeds. Treatments consisted of: constant temperatures of 23, 29, 35 and 41 °C, with photoperiods of 24 and 12 h of light, and alternating temperatures of 25-35 °C and 30-40 °C, with 12 h of light. Water content, germination, germination speed index, stem diameter, root length, shoot length, root dry mass and shoot dry mass of seedlings were evaluated. At 41 oC, S. macrophylla seeds failed to germinate. A constant temperature of 29 oC under 24 h of light favors the germination process of seeds and initial seedling growth.

Aflatoxins biosynthesis, toxicity and intervention strategies: A review

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Developing Countries ◽  
Molecular Basis ◽  
Genetic Regulation ◽  
Intervention Strategies ◽  
Historical Background ◽  
Economic Losses ◽  
Factors Affecting ◽  
Biomarkers Of Exposure ◽  
Food Commodities

Aflatoxins (AFTs) are toxic products of fungal metabolism, associated with serious health consequences and substantial economic losses to agriculture, livestock and poultry sectors, particularly in the developing countries. This review outlines the current information on AFTs in terms of historical background, classification, relative occurrence and co-existence with other mycotoxins in various food commodities. The phenomenon of aflatoxin (AFT) biosynthesis has been elucidated with reference to molecular basis, genetic regulation and factors affecting the AFT production. Moreover, the in vivo disposition kinetics, toxicological action and toxico-pathological consequences of AFTs have also been highlighted. Currently employed strategies for the detection and detoxification of AFTs, biomarkers of exposure assessment, potential economic impact and regulatory considerations regarding the AFTs have been emphasized.

Applicability of Instability Index for In vitro Protein Stability Prediction

2019 ◽  
Vol 26 (5) ◽  
pp. 339-347 ◽  
Author(s):  
Dilani G. Gamage ◽  
Ajith Gunaratne ◽  
Gopal R. Periyannan ◽  
Timothy G. Russell
Keyword(s):  
Protein Stability ◽  
Caulobacter Crescentus ◽  
Effect Of Temperature ◽  
Instability Index ◽  
Dipeptide Composition ◽  
Experimental Conditions ◽  
The Stability ◽  
Vitro Protein

Background: The dipeptide composition-based Instability Index (II) is one of the protein primary structure-dependent methods available for in vivo protein stability predictions. As per this method, proteins with II value below 40 are stable proteins. Intracellular protein stability principles guided the original development of the II method. However, the use of the II method for in vitro protein stability predictions raises questions about the validity of applying the II method under experimental conditions that are different from the in vivo setting. Objective: The aim of this study is to experimentally test the validity of the use of II as an in vitro protein stability predictor. Methods: A representative protein CCM (CCM - Caulobacter crescentus metalloprotein) that rapidly degrades under in vitro conditions was used to probe the dipeptide sequence-dependent degradation properties of CCM by generating CCM mutants to represent stable and unstable II values. A comparative degradation analysis was carried out under in vitro conditions using wildtype CCM, CCM mutants and two other candidate proteins: metallo-β-lactamase L1 and α -S1- casein representing stable, borderline stable/unstable, and unstable proteins as per the II predictions. The effect of temperature and a protein stabilizing agent on CCM degradation was also tested. Results: Data support the dipeptide composition-dependent protein stability/instability in wt-CCM and mutants as predicted by the II method under in vitro conditions. However, the II failed to accurately represent the stability of other tested proteins. Data indicate the influence of protein environmental factors on the autoproteolysis of proteins. Conclusion: Broader application of the II method for the prediction of protein stability under in vitro conditions is questionable as the stability of the protein may be dependent not only on the intrinsic nature of the protein but also on the conditions of the protein milieu.

scholarly journals Bioengineered Islet Cell Transplantation

2021 ◽  
Author(s):  
Kevin Bellofatto ◽  
Beat Moeckli ◽  
Charles-Henri Wassmer ◽  
Margaux Laurent ◽  
Graziano Oldani ◽  
...  
Keyword(s):  
State Of The Art ◽  
Diabetes Research ◽  
Islet Cell Transplantation ◽  
Β Cell ◽  
Cell Compartment ◽  
Factors Affecting ◽  
Insulin Activity ◽  
On Chip

Abstract Purpose of Review β cell replacement via whole pancreas or islet transplantation has greatly evolved for the cure of type 1 diabetes. Both these strategies are however still affected by several limitations. Pancreas bioengineering holds the potential to overcome these hurdles aiming to repair and regenerate β cell compartment. In this review, we detail the state-of-the-art and recent progress in the bioengineering field applied to diabetes research. Recent Findings The primary target of pancreatic bioengineering is to manufacture a construct supporting insulin activity in vivo. Scaffold-base technique, 3D bioprinting, macro-devices, insulin-secreting organoids, and pancreas-on-chip represent the most promising technologies for pancreatic bioengineering. Summary There are several factors affecting the clinical application of these technologies, and studies reported so far are encouraging but need to be optimized. Nevertheless pancreas bioengineering is evolving very quickly and its combination with stem cell research developments can only accelerate this trend.

scholarly journals Silver Nanoparticles and Their Antibacterial Applications

2021 ◽  
Vol 22 (13) ◽  
pp. 7202
Author(s):  
Tamara Bruna ◽  
Francisca Maldonado-Bravo ◽  
Paul Jara ◽  
Nelson Caro
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Agents ◽  
Multidrug Resistant ◽  
Secondary Effects ◽  
Cytotoxic Effects ◽  
Factors Affecting ◽  
Gram Positive Bacteria ◽  
Resistant Strains

Silver nanoparticles (AgNPs) have been imposed as an excellent antimicrobial agent being able to combat bacteria in vitro and in vivo causing infections. The antibacterial capacity of AgNPs covers Gram-negative and Gram-positive bacteria, including multidrug resistant strains. AgNPs exhibit multiple and simultaneous mechanisms of action and in combination with antibacterial agents as organic compounds or antibiotics it has shown synergistic effect against pathogens bacteria such as Escherichia coli and Staphylococcus aureus. The characteristics of silver nanoparticles make them suitable for their application in medical and healthcare products where they may treat infections or prevent them efficiently. With the urgent need for new efficient antibacterial agents, this review aims to establish factors affecting antibacterial and cytotoxic effects of silver nanoparticles, as well as to expose the advantages of using AgNPs as new antibacterial agents in combination with antibiotic, which will reduce the dosage needed and prevent secondary effects associated to both.

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