SEARCH · PubMed Health

Results for “Embryogenesis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 721 records · Page 40Linked to original sources

PubMed1997

Changes in late-embryogenesis-abundant (LEA) messenger RNAs and dehydrins during maturation and premature drying of Ricinus communis L. seeds.

In Ricinus communis L. (castor bean) endosperms, two classes of Late Embryogenesis Abundant (Lea) transcripts were first detected during mid-development (at 30-35 days after pollination, DAP) and peaked at 50 DAP, just prior to the onset of desiccation. Most of the Class I mRNAs declined substantially during desiccation itself; Class II mRNAs remained abundant in the mature dry (60 DAP) seed. Following imbibition, all Lea mRNAs abundant in the mature dry seed declined rapidly (within 5-24 h). Premature drying of developing 35-DAP seeds resulted in the loss of storage-protein mRNAs (Leg B Mat I); following rehydration, mRNAs encoding post-germinative proteins (Germ D91, D30 and D38) increased in the endosperm. The Lea mRNAs present in the developing fresh seed at 35 DAP were preserved, but did not increase in response to premature desiccation; upon rehydration these Lea mRNAs declined within 5 h. During seed development, substantial changes occurred in the synthesis of a subset of LEA proteins referred to as "dehydrins'; in particular, new dehydrin polypeptides were induced between 40 and 60 DAP. Such proteins were not as evident in prematurely dried endosperms. In contrast to the rapid loss of Lea mRNAs during germination, many of the dehydrin proteins abundant in the dried seed persisted following imbibition or rehydration.

Ricinus communis↗

PubMed1993

Zygotic transcription and cell proliferation during Drosophila embryogenesis.

The zygotic expression of only a few Drosophila genes is known to be required for completion of the normal embryonic mitoses. Molecular genetic analyses of these genes reveal that they fall into two classes, those whose mRNA levels are regulated in a stage and/or tissue-specific fashion to control cell cycle events during embryogenesis, and those in which, in the absence of functional zygotic expression, the maternal mRNA contribution does not provide sufficient product to complete the normal embryonic mitoses. Genes that comprise the first class are involved in the developmental control of the cell cycle, while those of the second class identify components of the cell cycle machinery.

Animals↗

PubMedDate not supplied

Distribution of fucosylated N-acetyl lactosamine carbohydrate determinants during embryogenesis of the kidney in man.

The monoclonal antibodies AGF4.48 and AGF4.36 raised against the promyeloid cell line HL60 recognise a fucosylated N-acetyl lactosamine determinant. This oligosaccharide sequence has been shown to be present on a variety of tissues at different developmental stages. Using the immunoperoxidase technique and the AGF4.48 and AGF4.36 antibodies on formalin-fixed, paraffin-embedded tissues, the distribution of the corresponding antigenic determinants during human renal embryogenesis has been studied. Both antibodies bind to the surface of the cells of the ampullae of the ingrowing ureteric bud branches, but not to the remainder of the ureteric bud. Reactivity at this site persists until after fusion of the ureteric bud with the S-shaped tubule, but is then lost. The determinants are also found on different segments of the proximal convoluted tubule in the foetal and adult kidney. The determinants are thus found on the cells responsible for induction of renal tubulogenesis, and separately at specific stages and functionally distinct sites on the developing tubule.

Adult↗

PubMed1976

Copper utilization during embryogenesis of Palaemon lamarrei.

The pattern of copper utilization during the embryogenesis of the freshwater prawn, Palaemon lamarrei has been described. Throughout the incubation period, lasting for 14 to 16 days, the egg of P. lamarrei is permeable to salts and against a concentration gradient, it absorbs 11 mug of salt from the freshwater medium. Out of this total salt uptake, as much as 0.143 mug is due to the absorption of copper. Intake of copper, as a function of incubation time, exhibit a more or less similar trend to that of total salt intake and this can be attributed to the increased synthesis of haemocyanin.

Animals↗

PubMed1976

Fatty acid biosynthesis during embryogenesis in the amphibian Bufo arenarum Hensel.

The fatty acid composition and biosynthesis of fatty acids were studied during early embryogenesis of the toad Bufo arenarum Hensel. The ova and stages up to the 6 1/2 day embryo have similar fatty acid compositions, with ca. 70% unsaturated acids. The eggs and embryo were permeable to acetate and impermeable to palmitic, linoleic, and eicosa-8, 11, 14-trienoic acid. Labeled acetate was incorporated by the eggs into the saturated acids-lauric, myristic, palmitic, stearic, arachidic, and behenic- and into the unsaturated acids-myristoleic, palmitoleic, oleic, and eicosaenoic acids. During segmentation and gastrulation, de novo biosynthesis of fatty acids increased, desaturation to myristoleic, palmitoleic, and oleic acids was enhanced; and fatty acids were esterified to triglycerides, phosphatidyl choline, and phosphatidyl ethanolamine. The feeding embryo (11 days) changed the pattern of incorporation to less incorporation into triglycerides.

8,11,14-Eicosatrienoic Acid↗

PubMed1992

Accumulation of vanadium during embryogenesis in the vanadium-rich ascidian, Ascidia gemmata.

It is a remarkable and previously unrecognized fact that ascidians, which are known to contain high levels of vanadium in their blood cells, begin to accumulate vanadium during embryogenesis. This study revealed that the accumulation starts quite dramatically 2 wk after fertilization, and 2 mo later, the amount of vanadium in larvae is 600,000 times higher than that in the unfertilized egg. These results were obtained by neutron activation analysis, a highly sensitive method for determining levels of vanadium, in the Ascidia gemmata, the ascidian that contains the highest known levels of vanadium and accumulates vanadium at 150 mM in its blood cells, a concentration that corresponds to 4,000,000 times the concentration in seawater.

Animals↗

PubMed1992

Congenital anomalies of the inferior vena cava: embryogenesis and MR features.

This article describes the MR appearances of the six most common congenital anomalies of the inferior vena cava. As a basis for understanding those anomalies, it describes the embryology of the inferior vena cava, based on an actual study of embryos and fetuses. The article takes a fresh look at the original research in this area, discusses the possible embryogenesis of the relevant anomalies, and describes different opinions on that subject, where different opinions exist.

Congenital Abnormalities↗

PubMed1997

Retinoid signalling and axial patterning during early vertebrate embryogenesis.

There are many indications that active retinoids are regulatory signals during vertebrate embryogenesis. Treating vertebrate embryos with retinoids can cause teratogenic defects, including specific derangements of the main body axis. Other data show that early vertebrate embryos contain physiologically relevant concentrations of active retinoids and express retinoid binding proteins and receptors; that knockouts of retinoid receptors can induce homeotic defects; and that relevant developmental control genes are regulated by retinoid response elements. Here, we discuss the possibility that retinoids are developmental signals which regulate axial patterning in the early vertebrate embryo.

Animals↗

PubMed2001

Differential expression of glucose transporters during chick embryogenesis.

The patterns of Glut1 and Glut3 glucose transporter protein and mRNA expression were assessed during embryogenesis of chicken brain and skeletal muscle, Glut4 protein levels were also evaluated in skeletal muscle and heart, and Glut1 was examined in the developing heart and liver. Glut1 protein expression was detectable throughout brain ontogeny but was highest during early development. Glut1 mRNA levels in the brain remained very high throughout development. Glut3 protein was highest very early and very late and mRNA was highest during the last half of development. In embryonic skeletal muscle, the levels of Glut1 and Glut3 proteins and mRNA were highest very early, and declined severely by mid-development. Glut1 protein and mRNA in the heart also peaked early and then decreased steadily. Although Glut1 mRNA levels were consistently high in the embryonic liver, Glut1 protein expression was not detected. These results suggest that (1) Glut1 is developmentally regulated in chick brain, skeletal muscle, and heart, (2) Glut1 mRNA is present in liver but does not appear to be translated, (3) Glut3 in brain increases developmentally but is virtually absent in muscle, and (4) Glut4 protein and mRNA appear to be absent from chick heart and skeletal muscle.

Animals↗

PubMed2003

Vegetative propagation of Quercus suber L. by somatic embryogenesis. II. Plant regeneration from selected cork oak trees.

The regeneration of somatic seedlings from selected 100-year-old cork oak trees is reported. The induction of somatic embryogenesis from leaves of epicormic shoots was significantly affected by genotype, harvesting time and their interaction. Leaves from all five selected trees produced somatic embryos when the segments of branches used as sources of epicormic shoots were collected in May. Genotype, but not the level of photosynthetically active radiation, affected the proliferation of the embryogenic lines and the number of detachable embryos that could be obtained from them. Genotype also affected several steps leading to conversion of somatic embryos, from germination to complete acclimatisation of somatic seedlings. Almost 40% of the somatic embryos from all lines germinated, showing coordinated root and shoot growth. Although the mean percentage of recovery for the whole process was low, plants could be regenerated from four of the five trees tested.

Acclimatization↗

PubMed2003

Auxin deprivation induces a developmental switch in maize somatic embryogenesis involving redistribution of microtubules and actin filaments from endoplasmic to cortical cytoskeletal arrays.

A developmental switch from non-polar pre-embryogenic units to polarized transition units in maize embryogenic callus is caused by auxin deprivation from the culture medium. This switch is accompanied by cytoskeletal rearrangements in embryogenic cells. An immunofluorescence study revealed prominent endoplasmic microtubules and actin filament meshworks radiating from the nuclear surfaces in pre-embryogenic cells growing on medium supplemented with auxin. On the other hand, parallel-organized cortical microtubules and cortical actin filament networks are inherently associated with polarized embryogenic cells of transition units growing on medium without auxin. These results indicate that fine-tuning of the dynamic equilibrium between endoplasmic and cortical cytoskeletal arrays is important for progress in somatic embryogenesis.

Actin Cytoskeleton↗

PubMed2003

Somatic embryogenesis and fertile green plant regeneration from suspension cell-derived protoplasts of rye ( Secale cereale L.).

A method for somatic embryogenesis and fertile green plant regeneration from suspension cell-derived protoplasts of rye (Secale cereale L. cv. Auvinen) was developed. Fast-growing and friable embryogenic calli with a high regeneration capacity were induced from immature rye inflorescences using modified MS medium. These friable embryogenic calli were used for suspension culture initiation in liquid AA medium. A high yield of protoplasts was obtained from suspension cell clumps after 3-5 days of subculture. Isolated protoplasts were cultured in KM8p medium. The frequency of protoplast cell divisions and colony formations in liquid culture medium were similar to those on agarose-solidified medium. Compact embryogenic calli were developed from protoplast-derived microcalli in growth medium mMS. Approximately 7% of the transferred embryogenic calli produced green shoots on N6 regeneration medium. Of 33 green plants, 28 were fertile with normal flowering and seed set. The ratio of green and albino plantlets was 1:4. Rye protoplast-derived green plants showed normal diploid characters as determined by flow cytometer analysis and chromosome counting.

Cell Division↗

PubMed2003

Somatic embryogenesis and plant regeneration from leaves of Ulmus minor Mill.

Somatic embryogenesis from mature elm ( Ulmus minor Mill.) in vitro-cloned material is possible. Embryogenic callus was obtained from leaves inoculated on two different MS-based media-one supplemented with 2.3 microM 2,4-dichlorophenoxyacetic acid (I2) and the other supplemented with 1.1 microM kinetin (I6). However, only leaves cultured on medium I6 produced somatic embryos, at the globular stage, when embryogenic callus was maintained in induction media. When embryogenic callus from medium I6 was transferred to basal medium, somatic embryos with green cotyledons were obtained. An average of 35.9% of these embryos converted easily into normal plants in conversion medium with 1% sucrose. Acclimatisation reached 39.7%, and this was not significantly different from a control group consisting of plants propagated by axillary buds. No morphological differences were observed between plants derived from somatic embryos and control plants. Also, no differences in ploidy were detected between the somatic embryo-derived plants and the mother plants.

2,4-Dichlorophenoxyacetic Acid↗

PubMed2004

Somatic embryogenesis in Solanum tuberosum L.: a histological examination of key developmental stages.

A potential novel method of producing high-quality potato ( Solanum tuberosum L.) nuclear seeds is through the process of somatic embryogenesis (SE). Somatic embryo formation has been successfully reported in many plant species, but in potato, reliable SE systems are still at the experimental stage. A key factor in the success of any SE system is the ability to discriminate SE-specific cellular structures from those emerging through an organogenic route. In the investigation reported here we attempted to discriminate the progression of specific stages of potato SE by histological means. Internodal segment (INS) explants from 4- to 6-week-old cv. Desiree in vitro cultures were successively cultured on SE induction (for 2 weeks) and expression/regeneration media (for 3 weeks) with and without 2,4-dichlorophenoxyacetic acid (5 microM). Microscopic examination of histological slides prepared using INS explants at different stages revealed the presence of characteristic globular, heart and torpedo stages in the potato SE system along with other associated unique features such as protoderm development and discrete vascular connections. These results confirm the occurrence of potato SE as per the accepted definition of the term.

2,4-Dichlorophenoxyacetic Acid↗

PubMed2005

Microspore embryogenesis and the development of a double haploidy protocol for cow cockle (Saponaria vaccaria).

Factors affecting microspore embryogenesis of cow cockle (Saponaria vaccaria) were evaluated including donor plant growing conditions, genotype, bud size, density, medium composition, and culture conditions. Of the two donor plant (day/night) temperature regimes evaluated (10/5 degrees C and 20/15 degrees C), plants grown at 20/15 degrees C were the most embryogenic. An embryogenic frequency of greater than 350 embryos/100 buds was observed in the most embryogenic genotype, cv. 'White Beauty'. Buds from 3-9 mm in length were evaluated for their embryogenic potential; buds that were 4-7.9 mm produced the most embryos/100 buds. Of all the media compositions evaluated, NLN medium with 15% sucrose resulted in the most embryos. Cow cockle microspores required an initial period of 32 degrees C for 3 days for production of microspore-derived embryos (MDEs).

Culture Media↗

PubMed2006

Plant regeneration through somatic embryogenesis from tissues of mature oak trees: true-to-type conformity of plantlets by RAPD analysis.

Somatic embryogenesis was induced in expanding leaf explants excised from epicormic shoots forced from branch segments taken at four different times of year from a mature oak (Quercus robur L.). Branch segments 2-4 cm in diameter produced most shoots when collected in March. Somatic embryos were induced on explants derived from branches of all collection dates, although collection in November seemed to afford the best results. Germination and conversion ability of embryos of embryogenic lines derived from six oak trees depended heavily on genotype, conversion rates ranging from 0 to 70%. RAPD analyses found no evidence of genetic variation either within or between the embryogenic lines established from three of these trees, or between these lines and the trees of origin, or between somatic embryo derived plantlets and the trees of origin. The embryogenic system used in this study appears to be suitable for true-to-type clonal propagation of mature oak genotypes.

Culture Media↗

PubMed2005

In vitro somatic embryogenesis from cell suspension cultures of cowpea [Vigna unguiculata (L.) Walp].

We report, an efficient protocol for plantlet regeneration from the cell suspension cultures of cowpea through somatic embryogenesis. Primary leaf-derived, embryogenic calli initiated in MMS [MS salts (Murashige and Skoog 1962) with B5 (Gamborg et al. 1968) vitamins] medium containing 2,4-Dichlorophenoxyacetic acid (2,4-D), casein hydrolysate (CH), and L: -Glutamic acid-5-amide (Gln). Fast-growing embryogenic cell suspensions were established in 0.5 mg l(-1) 2,4-D, which resulted in the highest recovery of early stages of somatic embryos in liquid MMS medium. Embryo development was asynchronous and strongly influenced by the 2,4-D concentration. Mature monocotyledonary-stage somatic embryos were induced in liquid B5 medium containing 0.1 mg l(-1) 2,4-D, 20 mg l(-1) L: -Proline (Pro), 5 muM Abscisic acid (ABA), and 2% mannitol. B5 medium was found superior for the maturation of somatic embryos compared to MS and MMS media. The importance of duration (5 d) for effective maturation of somatic embryos is demonstrated. A reduction in the 2,4-D level in suspensions increased the somatic embryo induction and maturation with decreased abnormalities. Sucrose was found to be the best carbon source for callus induction while mannitol for embryo maturation and maltose for embryo germination. Extension of hypocotyls and complete development of plantlet was achieved in half-strength B5 medium supplemented with 3% maltose, 2500 mg l(-1) potassium nitrate, and 0.05 mg l(-1) thidiazuron (TDZ) with 32% regeneration frequency. Field-established plants were morphologically normal and fertile. This regeneration protocol assures a high frequency of embryo induction, maturation, and plantlet conversion.

Cells, Cultured↗

PubMed2006

Refining the application of direct embryogenesis in sugarcane: Effect of the developmental phase of leaf disc explants and the timing of DNA transfer on transformation efficiency.

A rapid in vitro protocol using direct somatic embryogenesis and microprojectile bombardment was investigated to establish the developmental phases most suitable for efficient sugarcane transformation. Immature leaf roll disc explants with and without pre-emergent inflorescence tissue were compared. It was shown that for effective transformation to occur, explants should be cultured for several days to allow initiation of embryo development prior to bombardment. Leaf roll discs with pre-emergent inflorescences showed a higher degree of embryogenic competence than non-flowering explants, and transformation efficiency was higher when explants containing floral initials were bombarded. Despite the occurrence of high numbers of phenotypically negative plants, combining the use of inflorescent leaf roll discs with direct embryogenic regeneration has the potential to improve the speed and efficiency of transgenesis in sugarcane.

DNA, Plant↗