Search results for " embryo"

Simple high-performance liquid chromatographic assay for polyamines and their monoacetyl derivatives.

1993

A rapid reversed-phase high-performance liquid chromatographic method, using pre-column derivatization with benzoyl chloride and ultraviolet detection at 254 nm, was developed for the simultaneous measurement of polyamines and their monoacetyl derivatives. Calibration curves were linear for concentrations from 1.25 to 25 nmol/ml. The method was employed to assay these compounds in chick embryo retina explants using organic solvent extraction and 1,7-diaminoheptane as an internal standard. This simple and sensitive method can be applied to routine determinations of these compounds in various biological samples.

Chromatographic Characterization of Soluble Collagen in Sea Urchin Embryos (Paracentrotus Lividus)

1975

Genetic instability in calamondin (Citrus madurensis Lour.) plants derived from somatic embryogenesis induced by diphenylurea derivative

2007

Somatic embryos were regenerated in vitro from calamondin style-stigma explants cultured in the presence of N (6)-benzylaminopurine (BAP) cytokinin and three synthetic phenylurea derivatives, N-(2-chloro-4-pyridyl)-N-phenylurea (4-CPPU), N-phenyl-N'-benzothiazol-6-ylurea (PBU) and N,N'-bis-(2,3-methilendioxyphenyl)urea (2,3-MDPU). The phenylurea derivative compounds tested at micromolar level (12 muM) were able to induce a percentage of responsive explants significantly higher from that obtained with BAP and hormone-free (HF) conditions. In order to verify the genetic stability of the regenerants, 27 plants coming from different embryogenic events were randomly selected from each different …

Somatic embryogenesis and plant regeneration from pistil thin cell layers of Citrus

1999

Callus induction, somatic embryogenesis and plant regeneration were obtained in six different citrus species [Citrus deliciosa Ten. (cv 'Avana'), C.limon (L.) Burm. (cv 'Berna'), C.madurensis Lour. (cv 'CNR P9'), C.medica L. (cv 'Cedro di Trabia'), C.tardiva Hort. ex Tan. (cv 'CNR P6'), C.sinensis (L.) Osb. (cv 'Ugdulena 7')] from cultures of pistil transverse thin cell layer explants [(t)TCL]. Explants were cultured on three different media: the nutrients and vitamins of Murashige and Skoog medium alone (MS) or MS supplemented with either 500 mg l(-1) malt extract (MS I) or 500 mg l(-1) malt extract and 13.3 mu M 6-benzylaminopurine (MS II). Sucrose (146 mM) was used as the carbon source. …

1993

We may state that the path of development of an organism can play an important role in its immediate realization and also in its possible transformation. This leads to the problem of the existence of a causative link between individual development (ontogeny) and evolutionary history (phylogeny). This problem which has been dealt with by numerous authors, has led to contradictory answers, depending on the direction of the supposed connection: from the evolutionary history to individual development or vice versa, that is, from individual development to the evolutionary history.

Decreased temperature increases the expression of a disordered bacterial late embryogenesis abundant (LEA) protein that enhances natural transformati…

2021

Late embryogenesis abundant (LEA) proteins are important players in the management of responses to stressful conditions, such as drought, high salinity, and changes in temperature. Many LEA proteins do not have defined three-dimensional structures, so they are intrinsically disordered proteins (IDPs) and are often highly hydrophilic. Although LEA-like sequences have been identified in bacterial genomes, the functions of bacterial LEA proteins have been studied only recently. Sequence analysis of outer membrane interleukin receptor I (BilRI) from the oral pathogen Aggregatibacter actinomycetemcomitans indicated that it shared sequence similarity with group 3/3b/4 LEA proteins. Comprehensive …

Burst analysis tool for developing neuronal networks exhibiting highly varying action potential dynamics

2012

In this paper we propose a firing statistics based neuronal network burst detection algorithm for neuronal networks exhibiting highly variable action potential dynamics. Electrical activity of neuronal networks is generally analyzed by the occurrences of spikes and bursts both in time and space. Commonly accepted analysis tools employ burst detection algorithms based on predefined criteria. However, maturing neuronal networks, such as those originating from human embryonic stem cells (hESC), exhibit highly variable network structure and time-varying dynamics. To explore the developing burst/spike activities of such networks, we propose a burst detection algorithm which utilizes the firing s…

Gametic embryogenesis and haploid technology as valuable support to plant breeding

2011

Plant breeding is focused on continuously increasing crop production to meet the needs of an ever-growing world population, improving food quality to ensure a long and healthy life and address the problems of global warming and environment pollution, together with the challenges of developing novel sources of biofuels. The breeders' search for novel genetic combinations, with which to select plants with improved traits to satisfy both farmers and consumers, is endless. About half of the dramatic increase in crop yield obtained in the second half of the last century has been achieved thanks to the results of genetic improvement, while the residual advance has been due to the enhanced managem…

Cui prodest servāre? Due ipotesi di destinazione per gli embrioni crioconservati

2022

The essay analyses the general ban for the donation of embryos placed into cryopreservation, stated by the Italian legislation n. 40/2004. Such a prevision causes a sine die conservation not only for embryos suitable for implantation, but also for those affected by genetic defects or diseases. The essay points out that donating both types of embryos, respectively, to adoption or to scientific fertility research preserves the dignity of the cells in storage, as a will supported by the consent of both gametes’ providers to the ultimate scope of solidarity.

Zygotic and nucellar embryo survival following dehydration and cryopreservation of citrus intact seeds.

2004

A cryopreservation procedure by dehydration and direct immersion in liquid nitrogen was developed for seeds of four polyembryonic Citrus species, and the sexual or nucellar origin of the recovered seedlings was investigated. Seeds of three species could be desiccated in a sterile air flow to 16 percent (C. sinensis) or 10 percent (C. aurantium and C. limon) moisture content with a negligible reduction in germination levels. Differently, the germinability of C. deliciosa seeds dropped to 50 percent after drying to 15 percent moisture content. Following dehydration treatments, a reduction in the average number of seedlings per germinated seed was always observed. However, all four species ben…