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1

Somatic Embryogenesis in Chestnut  

Microsoft Academic Search

Somatic embryogenesis is an important biotechnological tool that demonstrates significant benefits\\u000a when applied to forest tree species; clonal propagation, cryostorage of valuable germoplasm and genetic\\u000a transformation are among the most promising of its applications. In this chapter, the state of the\\u000a art of somatic embryogenesis in chestnut (an important economical tree species of the genus Castanea) is assessed and discussed.

E. Corredoira; A. Ballester; F. J. Vieitez; A. M. Vieitez

2

Involvement of polyamine biosynthesis in somatic embryogenesis of Valencia sweet orange (Citrus sinensis) induced by glycerol.  

PubMed

Culture of Citrus sinensis embryogenic callus on the embryo-inducing medium (EIM) containing glycerol gave rise to a large number of embryos, whereas very few embryos were observed on the callus growth medium (CGM). In the current paper, attempts were made to investigate whether polyamine biosynthesis was involved in glycerol-mediated somatic embryogenesis. Quantification of free polyamines by high-performance liquid chromatography showed that the cultures on EIM had less putrescine than those on CGM. However, increase in spermidine and spermine was detected in cultures on EIM during the first 20d of culture, coincident with abundant somatic embryogenesis. The globular embryos contained more polyamines than embryos at other stages. Semi-quantitative reverse transcriptase-polymerase chain reaction assay showed that expression levels of all of the five key genes involved in polyamine biosynthesis, with the exception of S-adenosylmethionine decarboxylase, were induced in cultures on EIM, and that their transcriptional levels were increased with maturation of the embryos. Addition of alpha-difluoromethylornithine, a polyamine biosynthesis inhibitor, to EIM resulted in remarkable inhibition of somatic embryogenesis, concurrent with notable reduction of endogenous putrescine and spermidine, particularly at higher concentrations. Exogenous application of 1mM putrescine to EIM together with 5mM alpha-difluoromethylornithine led to dramatic enhancement of endogenous polyamines, which successfully restored somatic embryogenesis. All of these, collectively, demonstrated that free polyamines, at least spermidine and spermine herein, were involved in glycerol-mediated promotion of somatic embryogenesis, which will open a new avenue for establishing a sophisticated system for somatic embryogenesis based on the modulation of endogenous polyamines. PMID:18448195

Wu, Xiao-Ba; Wang, Jing; Liu, Ji-Hong; Deng, Xiu-Xin

2009-01-01

3

Stress induced acquisition of somatic embryogenesis in common bean Phaseolus vulgaris L.  

PubMed

Common bean Phaseolus vulgaris L. has been shown to be a recalcitrant plant to induce somatic embryogenesis (SE) under in vitro conditions. We used an alternative strategy to induce SE in common bean based upon the use of a cytokinin (BAP) coupled with osmotic stress adaptation instead of SE response that is induced by auxins. Explants derived from zygotic embryos of common bean were subjected to osmotic stress (sucrose 12 % w/v, 0.5 M) in the presence of BAP 10 mg/L and adenine free base 40 mg/L to induce somatic embryos from specific competent cells of the apical meristem and cotyledonary node. Somatic embryos were obtained from the competent cells in a direct response (direct SE). In a secondary response (secondary SE), those somatic embryos formed proembryogenic masses (PEM) that originated/developed into secondary somatic embryos and showed the SE ontogeny. Maturation of somatic embryos was achieved by using different osmolality media and converted to plants. Full-visible light spectrum was necessary to achieve efficient plant regeneration. Long-term recurrent SE was demonstrated by propagation of PEM at early stages of SE. This protocol is currently being applied for stable genetic transformation by means of Agrobacterium tumefaciens and bioballistics as well as for basic biochemical and molecular biology experiments. PMID:25252886

Cabrera-Ponce, José Luis; López, Liliana; León-Ramírez, Claudia G; Jofre-Garfias, Alba E; Verver-Y-Vargas, Aurora

2015-03-01

4

TDZ-induced direct shoot organogenesis and somatic embryogenesis on cotyledonary node explants of lentil (Lens culinaris Medik.).  

PubMed

An efficient and simple procedure for inducing high frequency direct shoot organogenesis and somatic embryogenesis in lentil from cotyledonary node explants (without both the cotyledons) in response to TDZ alone is reported. TDZ at concentration lower than 2.0 ?M induced shoot organogenesis whereas at higher concentration (2.5-15 ?M) it caused a shift in regeneration from shoot organogenesis to somatic embryogenesis. The cotyledonary node and seedling cultures developed only shoots even at high concentrations of BAP and TDZ, respectively. TDZ at 0.5 and 5.0 ?M was found to be optimal for inducing an average of 4-5 shoots per cotyledonary node in 93 % of the cultures and 55 somatic embryos in 68 % of the cultures, respectively. The somatic embryos were germinated when transferred to lower TDZ concentration (0.5-1.0 ?M). The shoots were rooted on MS basal medium containing 2.5 ?M IBA. The plantlets were obtained within 8 weeks from initiation of culture and were morphologically similar to seed-raised plants. The possible role of stress in thidiazuron induced somatic embryogenesis is discussed. PMID:23572901

Chhabra, Gulshan; Chaudhary, Darshna; Varma, Madan; Sainger, Manish; Jaiwal, Pawan K

2008-10-01

5

Regulation of Somatic Embryogenesis in Higher Plants  

Microsoft Academic Search

Somatic embryogenesis is the developmental process by which somatic cells undergo restructuring to generate embryogenic cells. These cells then go through a series of morphological and biochemical changes that result in the formation of a somatic or non-zygotic embryo capable of regenerating plants. Somatic embryogenesis represents a unique developmental pathway that includes a number of characteristic events: dedifferentiation of cells,

Xiyan Yang; Xianlong Zhang

2010-01-01

6

Somatic embryogenesis and Agrobacterium-mediated transformation of Japanese apricot ( Prunus mume) using immature cotyledons  

Microsoft Academic Search

This study describes a successful method of somatic embryogenesis and genetic transformation using immature cotyledons of Prunus mume. Immature cotyledons from four different developmental stages of eight different P. mume cultivars were used for the experiments to optimize somatic embryogenesis and genetic transformation protocols. Somatic embryogenesis was induced when the explants were cultured on somatic embryo inducing medium consisting of

Mei Gao; Makiko Kawabe; Tatsuya Tsukamoto; Hiromi Hanada; Ryutaro Tao

2010-01-01

7

Direct somatic embryogenesis and synthetic seed production from Paulownia elongata  

Microsoft Academic Search

We have developed a reproducible system for efficient direct somatic embryogenesis from leaf and internodal explants of Paulownia elongata. The somatic embryos obtained were subsequently encapsulated as single embryos to produce synthetic seeds. Several plant growth regulators [6-benzylaminopurine, indole-3-acetic acid, a-naphthaleneacetic acid, kinetin and thidiazuron (TDZ)] alone or in combination were tested for their capacity to induce somatic embryogenesis. The

Z. Ipekci; N. Gozukirmizi

2003-01-01

8

Walnut somatic embryogenesis: physiological and histological aspects  

E-print Network

Walnut somatic embryogenesis: physiological and histological aspects D. Cornu Amdlioration des and cultivated as described previously (Cornu, 1988). For histological studies, suitable tissue samples were

Paris-Sud XI, Université de

9

Culture-induced variation in plants of Coffea arabica cv. Caturra rojo, regenerated by direct and indirect somatic embryogenesis  

Microsoft Academic Search

Amplified fragment-length polymorphism (AFLP) was used to evaluate the stability of DNA in regenerated plantlets of Coffea arabica obtained by direct (DSE) and indirect somatic embryogenesis (ISE). Cluster analysis using the unweighted pair-group method\\u000a (UPGMA), showed no specific grouping pattern related to the type of embryogenesis. These results suggest that the somatic\\u000a embryogenesis (SE) process has a mechanism for the

L. Felipe Sanchez-Teyer; Francisco Quiroz-Figueroa; Victor Loyola-Vargas; Diogenes Infante

2003-01-01

10

Effect of hydrogen peroxide on somatic embryogenesis of Lycium barbarum L  

Microsoft Academic Search

The subject of this study is inducing somatic embryogenesis in the callus of Lyciumbarbarum L. and determining hydrogen peroxide in somatic embryogenesis. First of all, the activities of three antioxidant enzymes (SOD, peroxidase, catalase) in different stages of somatic embryogenesis were determined. The result showed that the activity of SOD gradually increased in the early days of differentiation culture and

Cui Kairong; Xing Gengsheng; Liu Xinmin; Xing Gengmei; Wang Yafu

1999-01-01

11

Uptake Rate of Tracer Elements by Lycium barbarum L. in Somatic Embryogenesis  

Microsoft Academic Search

The subject of this study was inducing somatic embryogenesis in the callus of Lycium barbarum L., The uptake rate of several metal ions in somatic embryogenesis was investigated by multitracer techniques. It was found that some metal ions changed the somatic embryogenesis dynamically. The uptake rates of metal ions were different from each other and exert mutual effect, mutual influence

Li Shan; Shen Zhenghu; Qin Zhi; Wang Yafu

2001-01-01

12

Secondary somatic embryogenesis and applications in plant breeding  

Microsoft Academic Search

Secondary somatic embryogenesis is the phenomenon whereby new somatic embryos are initiated from somatic embryos. Such cultures have been described in at least 80 Gymnosperm and Angiosperm species. In the initial step (primary somatic embryogenesis) such cultures have to be started from plant explants. In general, primary somatic embryogenesis from vegetative plant explants is, indirect and mostly driven by auxin

C. J. J. M. Raemakers; E. Jacobsen; R. G. F. Visser

1995-01-01

13

Somatic embryogenesis and plant regeneration of neem (Azadirachta indica A. Juss.)  

Microsoft Academic Search

Somatic embryos were initiated with mature seeds of neem (Azadirachta indica A. Juss.) when cultured on Murashige and Skoog's medium supplemented with thidiazuron (TDZ). Regeneration occurred via somatic\\u000a embryogenesis: direct embryo formation and through an intermediary callus phase. TDZ was very effective and induced somatic\\u000a embryogenesis across a wide range of concentrations (1–50 µm). However, somatic embryogenesis was accompanied by

B. N. S. Murthy; Praveen K. Saxena

1998-01-01

14

The analysis of differential gene expression in early somatic embryogenesis on Lycium barbarum  

Microsoft Academic Search

Direct exposure of calluses of Lycium barbarum L. to an auxin-free medium can induce somatic embryogenesis. Somatic\\u000a \\u000a embryogenesis of Lycium barbarum L. is controlled artificially by regulating 2,4-D concentration. The total RNA that was isolated from calluses, embryonic\\u000a calluses and early somatic embryos was used for analyzing differential genes expression. We obtained three cDNAs from early\\u000a somatic embryogenesis which were

Cui Kairong; Xing Gengsheng; Qin Lin; Liu Xinmin; Wang Yafu

1999-01-01

15

Somatic embryogenesis in wild cherry (Prunus avium)  

Microsoft Academic Search

Indirect somatic embryogenesis was obtained inPrunus avium L. from either somatic or zygotic embryos. An embryogenic line\\u000a was established by reinduction of embryogenic calluses from somatic embryos. The line was maintained for more than 3 years\\u000a through 6 generations of embryogenic cultures. In the last 2 generations, more than 50% of the explants were embryogenic.\\u000a Embryos at different stages of

Elisabeth Garin; Emmanuel Grenier; Ghislaine Grenier-De March

1997-01-01

16

Repetitive Somatic Embryogenesis of Ocotea catharinensis Mez. (Lauraceae): Effect of Somatic Embryo Developmental Stage and Dehydration  

Microsoft Academic Search

Repetitive embryogenesis of Ocotea catharinensis from globular\\/early cotyledonary somatic embryos was successfully supported by WPM supplemented with 22.7 g l?1 sorbitol, 20 g l?1 sucrose, 400 mg l?1 glutamine and 2 g l?1 Phytagel. The best medium to induce repetitive embryogenesis in cotyledonary somatic embryos was half strength WPM supplemented\\u000a with 20 g l?1 sucrose, 400 mg l?1 glutamine, 1.5

Alessandra dos Santos Olmedo; Geraldine de Andrade Meyer; Jonice Macedo; Wagner de Amorim; Ana Maria Viana

2004-01-01

17

Effect of Salicylic Acid on Somatic Embryogenesis and Plant Regeneration in Hedychium bousigonianum  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of this study was to induce somatic embryogenesis in Hedychium bousigonianum Pierre ex Gagnepain and assess the influence of salicylic acid (S) on somatic embryogenesis. Somatic embryos and subsequently regenerated plants were successfully obtained 30 days after transfer of embryogenic...

18

Somatic embryogenesis and organogenesis from immature embryo cotyledons of three sour cherry cultivars ( Prunus cerasus L.)  

Microsoft Academic Search

Immature cotyledons of open-pollinated fruits from three sour cherry cultivars (Prunus cerasus L.) were excised and cultured on Murashige and Skoog medium supplemented with various combinations of auxin and cytokinin to induce somatic embryogenesis. Somatic embryogenesis occurred principally when using the combinations of 2,4-dichlorophenoxyacetic acid plus kinetin. Using a-naphthaleneacetic acid or 6-benzylaminopurine reduced the incidence of somatic embryogenesis. Conversely, formation

Haoru Tang; Zhenglong Ren; Gabi Krczal

2000-01-01

19

Morphohistological analysis and histochemistry of Feijoa sellowiana somatic embryogenesis  

Microsoft Academic Search

Summary. Morphohistological analysis and histochemical studies were carried out during the induction and development of Feijoa sellowiana somatic embryos. Zygotic embryos were cultured on LPm medium containing 2,4-dichlorophenoxyacetic acid (20?µM) and glutamine (8?mM). Somatic embryogenesis could be induced from embryogenic cells that originated in meristematic centers or from clusters of cells. The presence of few starch grains and abundant protein

G. C. Cangahuala-Inocente; N. Steiner; M. Santos; M. P. Guerra

2004-01-01

20

Vegetative propagation of Quercus suber L. by somatic embryogenesis  

Microsoft Academic Search

Somatic embryogenesis was induced in expanding leaves from epicormic shoots forced to sprout from segments of branches collected from several hundred-year-old cork oak trees. Following a basic protocol previously defined for leaves taken from seedlings of this species, several factors were studied to improve the response. The induction frequency was significantly higher when the length of exposure to growth regulators

I. Hernández; C. Celestino; M. Toribio

2003-01-01

21

Somatic embryogenesis in Hedychium bousigonianum  

Technology Transfer Automated Retrieval System (TEKTRAN)

An efficient primary somatic embryo (SE) and secondary somatic embryo (SSE) production system was developed for the ornamental ginger Hedychium bousigonianum Pierre ex Gagnepain. Addition of two ethylene inhibitors, salicylic acid (SA) and silver nitrate (AgNO3), to the culture media improved the sy...

22

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

PubMed

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 culture condition and evaluated for somaclonal variations using inter-simple sequence repeat and random amplified polymorphic DNA analyses. We observed that 2,3-MDPU and PBU gave 3.7% of somaclonal mutants, whereas 4-CPPU gave 7.4% of mutants. No somaclonal variability was observed when plantlets were regenerated in BAP or HF medium. Although diphenylurea derivatives show a higher embryogenic potential as compared to BAP, they induce higher levels of somaclonal variability. This finding should be taken in consideration when new protocols for clonal propagation are being developed. PMID:17333016

Siragusa, Mirko; Carra, Angela; Salvia, Lidia; Puglia, Anna Maria; De Pasquale, Fabio; Carimi, Francesco

2007-08-01

23

Somatic embryogenesis in plantain banana  

Microsoft Academic Search

Summary  A cell suspension of French Sombre plantain banana (Musa spp. AAB genome) was initiated from callus obtained from young male flowers. Histological examination enabled us to describe and\\u000a follow the evolution of the suspension consisting of: embryogenic aggregates, proembryos, nodules, and isolated cells. It\\u000a demonstrated the unicellular origin of somatic embryos, either during maintenance of the suspension or after plating

A. Grapin; J. Schwendiman; C. Teisson

1996-01-01

24

Induction of somatic embryogenesis in Azadirachta indica  

Microsoft Academic Search

A modified culture protocol has been developed for the induction of somatic embryogenesis in Azadirachta indica (neem). Embryogenic calluses were initiated from cotyledons or hypocotyls using a Murashige and Skoog (MS) agar medium supplemented\\u000a with 0.5 mg l?1 ?-napthaleneacetic acid (NAA), 1 mg l?1 6-benzylaminopurine (BA), 1 g l?1 casein hydrolysate, and 50 g l?1 sucrose. The calluses, when transferred

Wei Wen Su; Wen-Ing Hwang; Se Young Kim; Yoneo Sagawa

1997-01-01

25

Stress induced somatic embryogenesis in carrot and its application to synthetic seed production  

Microsoft Academic Search

Summary  When apical meristems of carrot (Daucus carota L. cv. US-Harumakigosun) seedlings were cultured on hormone-free Murashige and Skoog’s (MS) medium with 0.7 M sucrose or\\u000a 0.25–1 mM cadmium ion, then transferred to hormone-free MS medium with 0.1 M sucrose, somatic embryos were formed on the surface\\u000a of the explants without visible callus formation. Somatic embryos were also formed on malformed

Hiroshi Kamada; Katsunori Kobayashi; Tomohiro Kiyosue; Hiroshi Harada

1989-01-01

26

Studies for Somatic Embryogenesis in Sweet Potato  

NASA Technical Reports Server (NTRS)

The purpose of this study was to improve the somatic embryo (SE) system for plant production of sweet potato (Ipomoea batatas L(Lam)). Explants isolated from SE-derived sweet potato plants were compared with control (non SE-derived) plants for their competency for SE production. Leaf explants were cultured on Murashige-Skoog (MS) medium with 2,4-dichlorophenoxy acetic acid (0.2 mg/L) and 6-benzylaminopurine (2.5 mg/L) for 2 weeks in darkness and transferred to MS medium with abscisic acid (2.5 mg/L). Explants isolated from those plants developed through somatic embryogenesis produced new somatic embryos rapidly and in higher frequency than those isolated from control plants They also appeared to grow faster in tissue culture than the control plants. Current studies in the laboratory are examining whether plants derived from a cyclical embryogenesis system (five cycles) would have any further positive impact on the rapidity and frequency of somatic embryo development. More detailed studies using electron microscopy are expected to show the point of origin of the embryos and to allow determination of their quality throughout the cyclical process. This study may facilitate improved plant micropropagation, gene transfer and germplasm conservation in sweet potato.

Bennett, J. Rasheed; Prakash, C. S.

1997-01-01

27

Studies on Somatic Embryogenesis in Sweetpotato  

NASA Technical Reports Server (NTRS)

The purpose of this study was to improve the somatic embryo (SE) system for plant production of sweetpotato Ipomoea batatas L.(Lam)l. Explants isolated from SE-derived sweet potato plants were compared with control (non SE-derived) plants for their competency for SE production. Leaf explants were cultured on Murashige-Skoog (MS) medium with 2,4-dichlorophenoxy acetic acid (0.2 mg/L) and 6-benzylaminopurine (2.5 mg/L) for 2 weeks in darkness and transferred to MS medium with abscisic acid (2.5 Explants isolated from those plants developed through somatic embryo-genesis produced new somatic embryos rapidly and in higher frequency than those isolated from control plants. They also appeared to grow faster in tissue culture than the control plants. Current studies in the laboratory are examining whether plants derived from a cyclical embryogenesis system (five cycles) would have any further positive impact on the rapidity and frequency of somatic embryo development. More detailed studies using electron microscopy are expected to show the point of origin of the embryos and to allow determination of their quality throughout the cyclical process. This study may facilitate improved plant micropropagation, gene transfer and germplasm conservation in sweet potato.

Bennett, J. Rasheed; Prakash, C. S.

1997-01-01

28

A new approach to direct somatic embryogenesis in Medicago  

Microsoft Academic Search

A highly efficient system for direct somatic embryogenesis is described. Leaf sections originating from young trifoliate leaves of Medicago falcata line 47\\/1–5 and Medicago sativa line No2\\/9R, directly produced embryos after cultivation in liquid B5IV induction medium. In comparison with indirect somatic embryogenesis the system omits the callus stage and thus allows shortening of the process of somatic embryogenesis in

P. Denchev; M. Velcheva; A. Atanassov

1991-01-01

29

Somatic embryogenesis and plant regeneration in Gymnema sylvestre  

Microsoft Academic Search

Somatic embryogenesis and whole plant regeneration were achieved in callus cultures derived from hypocotyl, cotyledon and leaf explants excised from seedlings of Gymnema sylvestre. Embryogenic callus was induced on Murashige and Skoog (MS) medium containing 2,4-D (0.5–5.0 µM) +BA (0.5–2.0 µM) and 2% (w\\/v) sucrose in 6–8 weeks of culture. Globular\\/heart stage embryos developed on induction medium. These embryos produced

H. G. Ashok Kumar; H. N. Murthy; K. Y. Paek

2002-01-01

30

Induction of somatic embryogenesis and DNA fingerprinting of Jojoba  

Microsoft Academic Search

In-vitro induction of somatic embryogenesis and regeneration ability of jojoba (Simmondsia chinensis (Link) Schneider) plant were investigated using two different types of explants, i.e., immature zygotic embryos and leaf disks, and different culture media. Compact embryogenic callus was induced on Murashige and Skoog (MS) medium supplemented with various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and sucrose. Embryogenic callus was developed from

Ahmed Gaber; Heba M. M. El-Maraghy; M. A. M. Aly; Nahed A. K. Rashed; A. Y. Gamal El-Din

31

Somatic embryogenesis in the medicinal legume Desmodium motorium (Houtt.) Merr  

Microsoft Academic Search

An efficient protocol was established for regeneration of Desmodium motorium via somatic embryogenesis. Embryogenic calli were induced from cotyledon segments (6 mm, 16 days old) lacking embryo axis,\\u000a excised from seedlings grown in vitro on Murashige and Skoog (MS) medium supplemented with indole-3-acetic acid (IAA) (2.9 ?M)\\u000a in combination with 6-benzyladenine (BA) (4.44 and 8.88 ?M). Differentiation of embryogenic calli into globular and heart-shaped\\u000a somatic

B. Chitra Devi; V. Narmathabai

2011-01-01

32

Role of trace elements in somatic embryogenesis A PIXE study  

NASA Astrophysics Data System (ADS)

Proton induced X-ray emission was used to study the trace elemental profiles of embryogenic and non-embryogenic callus of an important cash crop of India - Plantago ovata. Somatic embryogenesis, a well-known process for plant regeneration and crop improvement is modulated by various factors such as ionizing radiation and micro nutrients in the growth media. The present work reports the trace element variation in normal and irradiated callus tissue of P. ovata. Embryogenic and non-embryogenic callus tissues were exposed to gamma rays from a 60Co gamma source. The absorbed dose ranged from 10 to 100 Gy. Subsequent experiments showed significant dose dependent alterations in K, Ca, Mn, Fe, Ni, Cu, Zn, Br, Sr in both the embryogenic and non-embryogenic callus. The precise involvement of these elements has been discussed in light of somatic embryogenesis of the selected medicinal plant.

Saha, P.; Raychaudhuri, S.; Mishra, D.; Chakraborty, A.; Sudarshan, M.

2008-03-01

33

Spaceflight reduces somatic embryogenesis in orchardgrass (Poaceae)  

NASA Technical Reports Server (NTRS)

Somatic embryos initiate and develop from single mesophyll cells in in vitro cultured leaf segments of orchard-grass (Dactylis glomerata L.). Segments were plated at time periods ranging from 21 to 0.9 d (21 h) prior to launch on an 11 d spaceflight (STS-64). Using a paired t-test, there was no significant difference in embryogenesis from preplating periods of 14 d and 21 d. However, embryogenesis was reduced by 70% in segments plated 21 h before launch and this treatment was significant at P=0.0001. The initial cell divisions leading to embryo formation would be taking place during flight in this treatment. A higher ratio of anticlinal:periclinal first cell divisions observed in the flight compared to the control tissue suggests that microgravity affects axis determination and embryo polarity at a very early stage. A similar reduction in zygotic embryogenesis would reduce seed formation and have important implications for long-term space flight or colonization where seeds would be needed either for direct consumption or to grow another generation of plants.

Conger, B. V.; Tomaszewski, Z. Jr; McDaniel, J. K.; Vasilenko, A.

1998-01-01

34

A Novel In Vitro Protocol for Inducing Direct Somatic Embryogenesis in Phalaenopsis aphrodite without Taking Explants  

PubMed Central

An alternative in vitro protocol for embryo induction directly from intact living seedlings of Phalaenopsis aphrodite subspecies formosana was established in this study. Without the supplementation of plant growth regulators (PGRs), no embryos were obtained from all the seedlings when cultured on the solid medium. In contrast, embryos formed from the seedlings on the 2-layer medium and the 2-step culture system without the use of PGRs. It was found that the age of the seedlings affected embryo induction. The 2-month-old seedlings typically had higher embryogenic responses when compared with the 4-month-old seedlings in the 2-layer medium or 2-step system. For the 2-month-old seedlings, 1?mg/L TDZ resulted in the highest number of embryos at the distal site of the shoot. However, on the leaves' surface, 0.5?mg/L TDZ induced the highest number of embryos. When the 2-month-old seedlings were cultured using the 2-step method at 1?mg/L of TDZ, the highest embryogenic response was obtained, with an average of 44 embryos formed on each seedling. These adventitious embryos were able to convert into plantlets in a PGR-free 1/2 MS medium, and the plantlets had normal morphology and growth. PMID:24963505

Chen, Jen-Tsung

2014-01-01

35

A novel in vitro protocol for inducing direct somatic embryogenesis in Phalaenopsis aphrodite without taking explants.  

PubMed

An alternative in vitro protocol for embryo induction directly from intact living seedlings of Phalaenopsis aphrodite subspecies formosana was established in this study. Without the supplementation of plant growth regulators (PGRs), no embryos were obtained from all the seedlings when cultured on the solid medium. In contrast, embryos formed from the seedlings on the 2-layer medium and the 2-step culture system without the use of PGRs. It was found that the age of the seedlings affected embryo induction. The 2-month-old seedlings typically had higher embryogenic responses when compared with the 4-month-old seedlings in the 2-layer medium or 2-step system. For the 2-month-old seedlings, 1 mg/L TDZ resulted in the highest number of embryos at the distal site of the shoot. However, on the leaves' surface, 0.5 mg/L TDZ induced the highest number of embryos. When the 2-month-old seedlings were cultured using the 2-step method at 1 mg/L of TDZ, the highest embryogenic response was obtained, with an average of 44 embryos formed on each seedling. These adventitious embryos were able to convert into plantlets in a PGR-free 1/2 MS medium, and the plantlets had normal morphology and growth. PMID:24963505

Feng, Jia-Hua; Chen, Jen-Tsung

2014-01-01

36

Effect of hydrogen peroxide on synthesis of proteins during somatic embryogenesis in Lycium barbarum  

Microsoft Academic Search

Direct exposure of calluses of Lycium barbarum L. to an auxin-free medium can induce somatic embryogenesis. The effect of hydrogen peroxide on synthesis of proteins during somatic embryogenesis in Lycium barbarum L. was studied. One-dimensional gel electrophoresis showed that new protein was synthesized by embryogenic callus II (in MS+200 µmol l?1 H2O2 medium). Therefore, we suggested that there was a

Cui Kairong; Xing Gengmei; Wang Lihong; Wang Yafu

2002-01-01

37

Effect of hydrogen peroxide on synthesis of proteins during somatic embryogenesis in Lycium barbarum  

Microsoft Academic Search

Direct exposure of calluses of Lycium barbarum L. to an auxin-free medium can induce somatic embryogenesis. The effect of hydrogen peroxide on synthesis of proteins during somatic embryogenesis in Lycium barbarum L. was studied. One-dimensional gel electrophoresis showed that new protein was synthesized by embryogenic callus II (in MS+200 µmol l-1 H2O2 medium). Therefore, we suggested that there was a

Cui Kairong; Li Ji; Xing Gengmei; Li Jianlong; Wang Lihong; Wang Yafu

2002-01-01

38

Vegetative propagation of Quercus suber L. by somatic embryogenesis  

Microsoft Academic Search

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

I. Hernández; C. Celestino; J. Alegre; M. Toribio

2003-01-01

39

Papaver somniferum regeneration by somatic embryogenesis and shoot organogenesis  

Microsoft Academic Search

Secondary somatic embryogenesis and shoot organogenesis from primary somatic embryos of Papaver somniferum L. are described.\\u000a The embryos became malformed, the root meristem expressed dividing activity without position-dependent cell differentiation,\\u000a causing abnormal development or arrested growth of primary somatic embryos. The adventitious shoots regenerated from embryo\\u000a hypocotyl, but secondary somatic embryos had an epidermal origin close to the root meristem.

M. Ove?ka; M. Bobák; A. Blehová; J. Krištín

1997-01-01

40

Embryo production through somatic embryogenesis can be used to study cell differentiation in plants  

Microsoft Academic Search

Somatic embryogenesis is the process by which somatic cells, under induction conditions, generate embryogenic cells, which go through a series of morphological and biochemical changes that result in the formation of a somatic embryo. Somatic embryogenesis differs from zygotic embryogenesis in that it is observable, its various culture conditions can be controlled, and a lack of material is not a

Francisco R. Quiroz-Figueroa; Rafael Rojas-Herrera; Rosa M. Galaz-Avalos; Víctor M. Loyola-Vargas

2006-01-01

41

Somatic embryogenesis for efficient micropropagation of guava (Psidium guajava L.).  

PubMed

Guava (Psidium guajava L.) is well known for edible fruit, environment friendly pharmaceutical and commercial products for both national and international market. The conventional propagation and in vitro organogenesis do not meet the demand for the good quality planting materials. Somatic embryogenesis for efficient micropropagation of guava (P. guajava L.) has been developed to fill up the gap. Somatic embryogenesis and plantlets regeneration are achieved from 10-week post-anthesis zygotic embryo explants by 8-day inductive treatment with different concentrations of 2,4-dichlorophenoxy acetic acid (2,4-D) on MS agar medium containing 5% sucrose. Subsequent development and maturation of somatic embryos occur after 8 days on MS basal medium supplemented with 5% sucrose without plant growth regulator. The process of somatic embryogenesis shows the highest relative efficiency in 8-day treatment of zygotic embryo explants with 1.0 mg L(-1) 2,4-D. High efficiency germination of somatic embryos and plantlet regeneration takes place on half strength semisolid MS medium amended with 3% sucrose within 2 weeks of subculture. Somatic plantlets are grown for additional 2 weeks by subculturing in MS liquid growth medium containing 3% sucrose. Well-grown plantlets from liquid medium have survived very well following 2-4 week hardening process. The protocol of somatic embryogenesis is optimized for high efficiency micropropagation of guava species. PMID:23179697

Akhtar, Nasim

2013-01-01

42

Induction and establishment of somatic embryogenesis in elite Indian cotton cultivar (Gossypium hirsutumL. cv Khandwa-2)  

PubMed Central

Embryogenesis in cotton is a difficult task due its genome dependency. We used 3 cotton cultivars (Khandwa-2, G. Cot. 10, and BC-68–2) and Coker-312 as control for regeneration. Efficient somatic embryogenesis was induced in agronomically important Indian cotton cultivars, Khandwa-2 and G. Cot. 10. For callusing in all the cultivars, different media combinations were tried. Embryogenesis was initiated on a hormone-free MS medium (MSB). For embryo maturation and recovery excess of L-glutamine and l-asparagine were used. Khandwa-2 somatic embryos were successfully regenerated into plants. However, no plantlet was obtained in case of G. Cot. 10. Callus induction was also observed in BC-68–2 but there was no embryogenesis observed. The study indicated that the medium and genotype significantly effects embryogenesis. An efficient protocol is described here for regenerating plants via somatic embryogenesis in an elite Indian cotton cultivar Khandwa-2.

Kumar, Manoj; Singh, Harpal; Shukla, Anoop Kumar; Verma, Praveen Chandra; Singh, Pradhyumna Kumar

2013-01-01

43

Somatic Embryogenesis of Tylophora indica (Burm.f.) Merril., an Important Medicinal Plant  

Microsoft Academic Search

An efficient procedure has been developed for inducing somatic embryogenesis from mature leaves of Tylophora indica (Burm.f.) Merrill, an important medicinal plant. Leaf sections were initially cultured on Murashige and Skoog's (MS) medium supplemented with thidiazuron (TDZ) in addition with 2, 4-dichlorophenoxy acetic acid (2,4-D), particularly 0.5 µm TDZ along with 1.5 µm 2,4-D was very effective in inducing somatic

T. Chandrasekhar; T. Mohammad Hussain; G. Rama Gopal; J. V. Srinivasa Rao

2006-01-01

44

[Improvement of somatic embryogenesis process in sugarcane Venezuelan cultivars].  

PubMed

Efficient embryogenic callus formation (70%) in many sugarcane cultivars, has been established using young leaf explants cultivated on modified Murashige and Skoog medium containing 13 microM 2,4-dichlorophenoxiacetic acid (2,4-D). However, Venezuelan sugarcane cultivars V78-1 and V75-6 produced only 30% of embryogenic callus when were cultured in these conditions. In order to improve somatic embryogenesis in these Venezuelan cultivars, embryogenic calli were induced using different media: C3 (13 microM 2,4-D); C7 (31.5 microM 2,4-D); Cd (30 microM Dicamba) and C5BA (22.5 microM 2,4-D, 22.2 microM N6-Benzyladenine). After 45 days of induction, the highest embryogenic callus production (90%), was observed in both cultivars, when they were cultured on Cd medium. Moreover, plant development from somatic embryos originated in this callus, was evident four days after incubation on regeneration medium (without hormones), while the somatic embryos originated from calli growing in C3, C7 and C5BA media, gave rise to plants eight days after incubation on regeneration medium. PMID:12945490

Marcano, Ana Karina; Molina Guevara, Pedro; Oropeza, Maira; de García, Eva

2002-01-01

45

Plant regeneration via somatic embryogenesis in chickpea ( Cicer arietinum L.)  

Microsoft Academic Search

Efficient plant regeneration via somatic embryogenesis has been developed in chickpea cultivar C235. Leaf explants, on MS medium supplemented with 1.25 mg\\/l 2,4-D and 0.25 mg\\/l kinetin, yielded somatic embryos with high efficiency during dark incubation. MS medium supplemented with B5 vitamins, 0.125 mg\\/l IBA and 2 mg\\/l BAP was found suitable for embryo maturation. The well formed embryos germinated

V. Dinesh Kumar; P. B. Kirti; J. K. S. Sachan; V. L. Chopra

1994-01-01

46

A novel type of somatic embryogenesis in Coffea arabica  

Microsoft Academic Search

A novel type of somatic embryogenesis characterized by an efficient and highly synchronized embryo formation was observed in embryogenic callus of Coffea arabica initiated on Murashige and Skoog medium containing kinetin (4 mg\\/l) and 2,4-D (1 mg\\/l). It occurs in suspension and goes along with the suppression of “High Frequency Somatic Embryo Induction” (HFSE). This is achieved by favoring during

Beat Neuenschwander; Thomas W. Baumann

1992-01-01

47

Micropropagation of Panax notoginseng by somatic embryogenesis and RAPD analysis of regenerated plantlets  

Microsoft Academic Search

Somatic embryogenesis was induced in callus tissues derived from young flower buds of Panax notoginseng via callus within 18 weeks of culture. The mature somatic embryos were germinated on half-strength Murashige and Skoog's (MS) medium supplemented with gibberellic acid A3(GA) and 6-benzyladenine (BA). The most suitable medium for optimal root formation proved to be MS medium supplemented with 1-naphthaleneacetic acid

Y. Shoyama; Xuan Xuan Zhu; R. Nakai; S. Shiraishi; H. Kohda

1997-01-01

48

An efficient regeneration system via direct and indirect somatic embryogenesis for the medicinal tree Murraya koenigii  

Microsoft Academic Search

A reproducible protocol for direct and indirect somatic embryogenesis was established in a small aromatic tree, Murraya koenigii. Embryogenic callus was obtained from 90% zygotic embryonic axis (ZE) and 70% cotyledon (COT) explants in Murashige and Skoog\\u000a (MS) basal medium supplemented with 8.88 ?M 6-benzyladenine (BA) and 2.675 ?M ?-naphthaleneacetic acid (NAA). Globular somatic\\u000a embryos were induced and further matured from such

S. Paul; A. Dam; A. Bhattacharyya; T. K. Bandyopadhyay

2011-01-01

49

Induction of plant somatic embryogenesis in liquid medium  

Microsoft Academic Search

The large scale propagation of plants via somatic embryogenesis, has so far been difficult to achieve. In this thesis research is described leading to embryogenic cell lines that can be maintained for a long period, without loss of genetic stability. It is also described how embryogenic potential of cell lines can be influenced by the addition of specific arabinogalactan-proteins.We consider

M. Kreuger

1996-01-01

50

Somatic Embryogenesis in Mature Quercus Robur Trees  

Microsoft Academic Search

Somatic embryo induction and plant regeneration have been obtained in tissues from mature Quercus robur L. trees. Epicormic shoots were forced to flush in branch segments collected from the crown of trees growing in selected stands on different collection dates. Expanding leaves from five genotypes, cultured following a multistage treatment procedure, produced somatic embryos at frequencies ranging from 0.3 to

M. Toribio; C. Fernández; C. Celestino; M. T. Martínez; A. M. Vieitez

2004-01-01

51

A new approach to direct somatic embryogenesis in Medicago.  

PubMed

A highly efficient system for direct somatic embryogenesis is described. Leaf sections originating from young trifoliate leaves of Medicago falcata line 47/1-5 and Medicago sativa line No2/9R, directly produced embryos after cultivation in liquid B5IV induction medium. In comparison with indirect somatic embryogenesis the system omits the callus stage and thus allows shortening of the process of somatic embryogenesis in alfalfa by 35-40 days. It permits the avoidance of secondary changes occurring during the process of dedifferentiation. A modified B5/3H medium containing Polyethylene Glycol 6000 promoted embryo development from globular up to torpedo stage. It was clearly shown that 2.5% Polyethylene Glycol stimulated this process for both H. falcata 47/1-5 and M. sativa No 2/9R. Maturation of torpedo stage embryos was carried out on solidified or liquid abscisic acidcontaining medium. A 30?M abscisic acid concentration was optimal in allowing one embryo to yield one plant. Somatic embryo conversion to plants and plant regeneration was performed on Murashige and Skoog medium. Regenerated plants showed a normal morphology. PMID:24221669

Denchev, P; Velcheva, M; Atanassov, A

1991-09-01

52

Somatic embryogenesis from Sorghum bicolor leaves  

Microsoft Academic Search

Plant regeneration from totipotent cultured cells or protoplasts is a prerequisite for the often proposed genetic modification of plants through somatic cell genetics, and has been achieved in many species. The cereals (and the rest of the Gramineae) have, however, proved to be extremely unresponsive to in vitro culture techniques1. The most convenient source of plant protoplasts is the leaf

Wolfgang Wernicke; Richard Brettell

1980-01-01

53

Alternative oxidase involvement in Daucus carota somatic embryogenesis.  

PubMed

Plant alternative oxidase (AOX) is a mitochondrial inner membrane enzyme involved in alternative respiration. The critical importance of the enzyme during acclimation upon stress of plant cells is not fully understood and is still an issue of intensive research and discussion. Recently, a role of AOX was suggested for the ability of plant cells to change easily its fate upon stress. In order to get new insights about AOX involvement in cell reprogramming, quantitative real-time polymerase chain reaction (PCR) and inhibitor studies were performed during cell redifferentiation and developmental stages of Daucus carota L. somatic embryogenesis. Transcript level analysis shows that D. carota AOX genes (DcAOX1a and DcAOX2a) are differentially expressed during somatic embryogenesis. DcAOX1a shows lower expression levels, being mainly down-regulated, whereas DcAOX2a presented a large up-regulation during initiation of the realization phase of somatic embryogenesis. However, when globular embryos start to develop, both genes are down-regulated, being this state transient for DcAOX2a. In addition, parallel studies were performed using salicylhydroxamic acid (SHAM) in order to inhibit AOX activity during the realization phase of somatic embryogenesis. Embryogenic cells growing in the presence of the inhibitor were unable to develop embryogenic structures and its growth rate was diminished. This effect was reversible and concentration dependent. The results obtained contribute to the hypothesis that AOX activity supports metabolic reorganization as an essential part of cell reprogramming and, thus, enables restructuring and de novo cell differentiation. PMID:19863756

Frederico, António Miguel; Campos, Maria Doroteia; Cardoso, Hélia Guerra; Imani, Jafargholi; Arnholdt-Schmitt, Birgit

2009-12-01

54

Plant regeneration via somatic embryogenesis and shoot organogenesis from immature cotyledons of Camellia nitidissima Chi.  

PubMed

Camellia nitidissima Chi (Theaceae) is a world-famous economic and ornamental plant with golden-yellow flowers. It has been classified as one of the rarest and most endangered plants in China. Our objective was to induce somatic embryogenesis, shoot organogenesis and plant regeneration for C. nitidissima. Three types of callus (whitish, reddish and yellowish) were induced from immature cotyledons on improved woody plant medium (WPM) with different plant growth regulators (PGRs). Among the callus, whitish callus was induced by 4.5 ?M 2,4-dichlorophenoxyacetic acid (2,4-D) and reddish and yellowish callus were induced by strongly active cytokinins, thidiazuron (TDZ) or 6-benzylaminopurine (BAP), singly or combined with weakly active auxin, ?-naphthaleneacetic acid (NAA). The embryogenic callus could differentiate into somatic embryos, nodular embryogenic structures (large embryo-like structures) or adventitious shoots depending on the PGR used in WPM. BAP was best for adventitious buds and zeatin was best for somatic embryogenesis while kinetin (Kt) was best for the formation of nodular embryogenic structures. The three regeneration pathways often occurred in the same embryogenic callus clumps. Most shoots (80.0%) developed roots in WPM supplemented with 24.6 ?M IBA and 0.3 ?M NAA while 47.5% of somatic embryos could germinate directly and develop into plantlets on induction medium supplemented with 0.9 ?M BAP and 0.1 ?M NAA. The nodular embryogenic structures could be sub-cultured and cyclically developed in one of two differentiation pathways: shoot organogenesis or somatic embryogenesis. Plantlets derived from shoot buds rooted and somatic embryos germinated when transplanted into soil in a greenhouse; 66.7% of plantlets from shoot culture and 78.6% of plantlets from somatic embryos survived after 8 weeks' acclimatization. PMID:23790533

Lü, Jinfeng; Chen, Rong; Zhang, Muhan; da Silva, Jaime A Teixeira; Ma, Guohua

2013-09-01

55

Somatic embryogenesis and plant regeneration of northern red oak ( Quercus rubra L.)  

Microsoft Academic Search

A somatic embryogenesis protocol for plant regeneration of northern red oak (Quercus rubra) was established from immature cotyledon explants. Embryogenic callus cultures were induced on Murashige and Skoog medium\\u000a (MS) containing 3% sucrose, 0.24% Phytagel™, and various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-d) after 4 weeks of culture in darkness. A higher response (66%) of embryogenic callus was induced on 0.45 ?M 2,4-d.

G. Vengadesan; Paula M. Pijut

2009-01-01

56

Cold-enhanced somatic embryogenesis in cell suspension cultures of Astragalus adsurgens Pall.: relationship with exogenous calcium during cold pretreatment  

Microsoft Academic Search

The inter-relationship between exogenous calcium (Ca2+) during cold pretreatment and cold-enhanced somatic embryogenesis was investigated using cell suspension cultures of Astragalus adsurgens Pall. Cell suspension was obtained from embryogenic callus and could be induced to form somatic embryos in the differentiation medium. Suspension cells, after cold-treatment at 8 °C for 2 to 3 wk, displayed an enhanced capacity for somatic

Jian-Ping Luo; Shao-Tong Jiang; Li-Jun Pan

2003-01-01

57

Pepper ( capsicum annuum L.) regenerants obtained by direct somatic embryogenesis fail to develop a shoot  

Microsoft Academic Search

Summary  Three auxin-type herbicides, namely 2.4-dichlorophenoxyacetic acid (2,4-D), (4-chlorophenoxy)acetic acid 2-(dimethylamino)ethyl\\u000a ester (centrophenoxine), and quinolinecarboxylic acid (quinclorac) induced direct somatic embryogenesis in seed-derived zygotic\\u000a embryo explants of sweet pepper (Capsicum annuum L.) when added to Murashige and Skoog medium with 200 mM sucrose. Optimum concentrations for embryogenesis induction were 0.40–0.45 mM and 1.15–1.30 ?M for 2.4-D and centrophenoxine, respectively (in the

Benjamin Steinitz; Mustafa Küsek; Yona Tabib; Ilan Paran; Aaron Zelcer

2003-01-01

58

Development of a cyclic somatic embryogenesis regeneration system for leek (Allium ampeloprasum L.) using zygotic embryos.  

PubMed

In leek (Allium ampeloprasum L.) a cyclic system of somatic embryogenesis was developed. Somatic embryos used for cyclic embryogenesis were able to develop the same type of embryogenic callus as zygotic embryos in the primary cycle. For the first time a comparison of the efficiencies of both expiants was made. Ten families were investigated for somatic embryogenesis. There was a genetic relationship with respect to somatic embryo production between the reciprocal crosses. From each family one genotype was selected for investigating cyclic somatic embryogenesis. Different levels of somatic embryo production were found between the expiants of zygotic and somatic embryos. The two best genotypes, 92.001-03 and 92.002-33 produced twice as many somatic embryos as the overall average. On average, 56% of the somatic embryos finally developed into greenhouse plantlets. PMID:24190300

Schavemaker, C M; Jacobsen, E

1995-01-01

59

Loss of competence for glyoxysome formation during somatic embryogenesis in anise ( Pimpinella anisum L.) suspension cultures  

Microsoft Academic Search

Somatic embryogenesis in anise (Pimpinella anisum L.) suspension cultures induced by transfer to hormone-free growth medium may be synchronized by previous selection of cell aggregates with diameters between 100–240 µm. Around 80–90% of the embryoids are globular after 2–3 d, heart-shaped after 5–7 d and torpedo-shaped after 9 d. In embryogenic medium without source of carbon or with 20 mmol\\/l

R. A. Kudielka; R. R. Theimer

1983-01-01

60

High frequency somatic embryogenesis and plant regeneration in callus cultures of Astragalus adsurgens Pall  

Microsoft Academic Search

Efficient plant regeneration through somatic embryogenesis was achieved in Astragalus adsurgens. Embryogenic callus was induced from hypocotyl, not root or cotyledon explants, and the maximum induction frequency (62%) was obtained on Murashige and Skoog (1962) basal medium (MS) containing 2.0 mg\\/l 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 mg\\/l N6-benzylaminopurine (BA). Transfer of embryogenic calli to MS medium with 1–2 mg\\/l BA

Jian-Ping Luo; Jing-Fen Jia; Yue-Hua Gu; Jing Liu

1999-01-01

61

The effects of ancymidol, abscisic acid, uniconazole and paclobutrazol on somatic embryogenesis of asparagus  

Microsoft Academic Search

Summary  The effects of ancymidol, abscisic acid (ABA), uniconazole, and paclobutrazol on asparagus somatic embryogenesis were evaluated. Calli induced from seedlings of genotype G447 were transferred to embryo induction medium (MS plus 3% sucrose, 0.1 mg L–1 NAA, 0.5 mg L–1 kinetin and 3% gelrite), with different concentrations of these compounds. After 8 weeks, the recovered bipolar or globular embryos were

Baochun Li; David J. Wolyn

1995-01-01

62

Plant regeneration via somatic embryogenesis in ginger  

Microsoft Academic Search

Embryogenic callus cultures of ginger were induced from young leaf segments taken from in vitro shoot cultures. Among the four auxins tested in Murashige & Skoog medium, dicamba at 2.7 µM was most effective in inducing and maintaining embryogenic cultures. Efficient plant regeneration was achieved when embryogenic cultures were transferred to Murashige & Skoog medium containing 8.9 µM benzyladenine. Histological

A. Kackar; S. R. Bhat; K. P. S. Chandel; S. K. Malik

1993-01-01

63

Somatic embryogenesis of tissue cultures of Papaver somniferum and Papaver orientale and its relationship to alkaloid and lipid metabolism  

Microsoft Academic Search

Transfer from complete to 2,4-D free Gamborg's B5-medium efficiently induced somatic embryogenesis in Papaver tissue cultures (P. somniferum and P. orientale). Embryogenesis was preceded by a strong temporary accumulation of triacylglycerols. In both tissue cultures large amounts of sanguinarine type alkaloids were present, which disappeared during regeneration in the P. orientale cultures but persisted in the P. somniferum cultures. In

R. Schuchmann; E. Wellmann

1983-01-01

64

High-frequency plant regeneration through cyclic secondary somatic embryogenesis in black pepper ( Piper nigrum L.)  

Microsoft Academic Search

A high-frequency plantlet regeneration protocol was developed for black pepper (Piper nigrum L.) through cyclic secondary somatic embryogenesis. Secondary embryos formed from the radicular end of the primary somatic embryos which were originally derived from micropylar tissues of germinating seeds on growth regulator-free SH medium in the absence of light. The process of secondary embryogenesis continued in a cyclic manner

R. Ramakrishnan Nair; S. Dutta Gupta

2006-01-01

65

Somatic embryogenesis in sisal ( Agave sisalana Perr. ex. Engelm).  

PubMed

A protocol has been developed for somatic embryogenesis and plant regeneration of sisal (Agave sisalana Perr. ex. Engelm). Embryogenic callus cultures were initiated from young shoots raised in vitro from the stem portion of the bulbil on medium supplemented with 1-2 mg l(-1) kinetin (KN) and 0.2-0.5 mg l(-1) alpha-naphthaleneacetic acid plus KN or 1-1.5 mg l(-1 )benzylaminopurine (BAP) or 0.25-0.5 mg l(-1 )2,4-dichlorophenoxyacetic acid plus BAP or 0.5-1.0 mg l(-1) KN. Embryos at various developmental stages (globular-, heart- or torpedo-shaped) produced mature and germinating embryos on being transferred to a new medium containing 0-0.25 mg l(-1 )KN. After 28 days, a maximum of 76% germinated embryos was obtained on a medium supplemented with 0.1 mg l(-1) KN. The capacity for embryogenesis remained constant in the callus upon subculturing on the same medium for more than 48 months. Histological observations showed a distinct multicellular origin for most of the somatic embryos as they developed from epidermal, sub-epidermal and inside callus cells, while a few of them originated from a superficial callus cell. Plantlets regenerated from embryos were transferred to the field where their survival rate was 100%. PMID:12920563

Nikam, T D; Bansude, G M; Aneesh Kumar, K C

2003-10-01

66

Proteome analysis of early somatic embryogenesis in Picea glauca.  

PubMed

Forestry is a valuable natural resource for many countries. Rapid production of large quantities of genetically improved and uniform seedlings for restocking harvested lands is a key component of sustainable forest management programs. Clonal propagation through somatic embryogenesis has the potential to meet this need in conifers and can offer the added benefit of ensuring consistent seedling quality. Although in commercial use, mass production of conifers through somatic embryogenesis is relatively new and there are numerous biological unknowns regarding this complex developmental pathway. To aid in unravelling the embryo developmental process, two-dimensional electrophoresis was employed to quantitatively assess the expression levels of proteins across four stages of somatic embryo maturation in white spruce (0, 7, 21 and 35 days post abscisic acid treatment). Forty-eight differentially expressed proteins have been identified, which display a significant change in abundance as early as day 7 of embryo development. These proteins are involved in a variety of cellular processes, many of which have not previously been associated with embryo development. The identification of these proteins was greatly assisted by the availability of a substantial expressed sequence tag (EST) resource developed for white, sitka and interior spruce. The combined use of these spruce ESTs in conjunction with GenBank accessions for other plants improved the rate of protein identification from 38% to 62% when compared with GenBank alone using automated, high-throughput techniques. This underscores the utility of EST resources in a proteomic study of any species for which a genome sequence is unavailable. PMID:15627954

Lippert, Dustin; Zhuang, Jun; Ralph, Steven; Ellis, Dave E; Gilbert, Margarita; Olafson, Robert; Ritland, Kermit; Ellis, Brian; Douglas, Carl J; Bohlmann, Jörg

2005-02-01

67

Somatic embryogenesis and in vitro rosmarinic acid accumulation in Salvia officinalis and S. fruticosa leaf callus cultures  

Microsoft Academic Search

The effect of explant age, plant growth regulators and culture conditions on somatic embryogenesis and rosmarinic acid production\\u000a from leaf explants of Salvia officinalis and S. fruticosa plants collected in Greece was investigated. Embryogenic callus with numerous spherical somatic embryos could be induced\\u000a on explants derived from both species and cultured for 3 weeks on a Murashige and Skoog (MS)

S. Kintzios; A. Nikolaou; M. Skoula

1999-01-01

68

Cyclic secondary somatic embryogenesis and efficient plant regeneration in camphor tree ( Cinnamomum camphora L.)  

Microsoft Academic Search

An efficient protocol for secondary somatic embryogenesis in camphor tree is reported. Secondary somatic embryos (SSEs), initially\\u000a obtained from the primary embryos of a nascent embryogenic culture in 2002, were proliferated and maintained for more than\\u000a 4 yr via cyclic secondary somatic embryogenesis. Throughout this period, the embryo populations retained a high level of competence\\u000a for plant regeneration. SSEs were produced

Xueping Shi; Xigang Dai; Guofeng Liu; Junwei Zhang; Guogui Ning; Manzhu Bao

2010-01-01

69

First Report of Plant Regeneration via Somatic Embryogenesis from Shoot Apex-derived Callus of Hedychium muluense  

Technology Transfer Automated Retrieval System (TEKTRAN)

Plants were successfully regenerated via somatic embryogenesis from shoot apex-derived callus of Hedychium muluense R.M. Smith, an important monocotyledonous ornamental ginger plant. Callus was induced on a modified Murashige and Skoog (MS) medium supplemented with 9.05 µM 2-4, D and 4.6µM kinetin. ...

70

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

Microsoft Academic Search

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

S. Valladares; C. Sánchez; M. T. Martínez; A. Ballester; A. M. Vieitez

2006-01-01

71

Expression of PiABP19, Picdc2 and PiSERK3 during induction of somatic embryogenesis in leaflets of Prunus incisa (Thunb.).  

PubMed

Somatic embryogenesis is a useful tool of plant breeding. In this context, a procedure for inducing somatic embryogenesis in Prunus incisa leaf explants had been previously developed. The original in vitro protocol relies on picloram treatments and exposure to darkness as inductive conditions, the best frequency of embryogenesis being obtained on the second leaf (F(2)) exposed to 4 ?M picloram during 30 days. The morphological and biochemical changes observed during somatic embryogenesis occur in response to alterations in gene expression regulation patterns. A molecular study was conducted in order to provide deeper insight into the fundamental biological factors involved in the induction of this process using a gene candidate strategy and semi-quantitative reverse transcription polymerase chain reaction analysis. So far, no sequence data related to somatic embryogenesis has been available in cherry. In the present study, we cloned and sequenced cDNA fragments of putative genes encoding auxin-binding protein, cell cycle regulator and somatic embryogenesis receptor kinase. Time-course differential transcript accumulations were observed for all investigated genes in leaves or derived callus tissues during the observation period (first month of culture). Their possible involvement in the sequential steps of the embryogenic pathway (dedifferentiation, cell proliferation, differentiation through somatic embryogenesis) is presented and discussed. PMID:23086274

Ben Mahmoud, Kaouther; Delporte, Fabienne; Muhovski, Yordan; Elloumi, Nadhra; Jemmali, Ahmed; Druart, Philippe

2013-02-01

72

Micropropagation of Citrus spp. by organogenesis and somatic embryogenesis.  

PubMed

Citrus spp., the largest fruit crops produced worldwide, are usually asexually propagated by cuttings or grafting onto seedling rootstocks. Most of Citrus genotypes are characterized by polyembryony due to the occurrence of adventive nucellar embryos, which lead to the production of true-to-type plants by seed germination. Tissue culture and micropropagation, in particular, are valuable alternatives to traditional propagation to obtain a high number of uniform and healthy plants in a short time and in a small space. Moreover, in vitro propagation provides a rapid system to multiply the progeny obtained by breeding programs, allows the use of monoembryonic and seedless genotypes as rootstocks, and it is very useful also for breeding and germplasm preservation.In this chapter, two protocols regarding organogenesis of a rootstock and somatic embryogenesis of a cultivar have been described. PMID:23179693

Chiancone, Benedetta; Germanŕ, Maria Antonietta

2013-01-01

73

Improvements of cyclic somatic embryogenesis of cassava (Manihot esculenta Crantz).  

PubMed

In cassava a cyclic system of somatic embryogenesis was developed. Primary (torpedo shaped or germinated) embryos, originating from leaf lobes, could only be obtained after culture on solid medium. Cyclic embryos, originating from embryos, could be obtained in both liquid and on solid medium. The production of embryos in liquid medium was distinctly higher, faster and more synchronized than on solid medium. Lower densities and fragmentation of starting embryos improved the production significantly. The highest production found was 32.1 embryos per initial embryo. In all treatments the explants initiated multiple embryos. The production of single embryos was achieved by pressing starting embryos through a fine meshed sieve, indicating that embryos can be produced from a piece of tissue with a restricted number of cells. The shoot conversion rate of embryos from liquid medium was comparable with that of embryos from solid medium. PMID:24197025

Raemakers, C J; Schavemaker, C M; Jacobsen, E; Visser, R G

1993-02-01

74

Induction of high-frequency somatic embryogenesis in geranium (Pelargonium x hortorum Bailey cv Ringo Rose) cotyledonary cultures.  

PubMed

The cv Ringo Rose of hybrid seed geranium (Pelargonium x hortorum Bailey), previously shown to be recalcitrant in culture, produced somatic embryos when cotyledonary explants were cultured on regeneration medium containing thidiazuron (TDZ), forchlorfenuron (CPPU), or a combination of indole-3-acetic acid and N(6) benzylaminopurine (IAA+BAP). Amendment of the basal medium with TDZ (0.5 ?M) was the most effective treatment. Addition of amino acids to the medium promoted the growth of somatic embryos. Retention of the proximal region of the cotyledon was crucial for regeneration, but the removal of the distal 1/3 to 1/2 cotyledon had no significant effect on somatic embryogenesis. Cotyledonary explants formed somatic embryos in higher frequency and much earlier than hypocotyl explants cultured on the same medium. The somatic embryos induced on cotyledonary explants were germinated on basal medium. More than 70% of the somatic embryos were converted into plants and transferred to soil. PMID:24178422

Murthy, B N; Singh, R P; Saxena, P K

1996-02-01

75

Metabolic footprinting study of white spruce somatic embryogenesis using NMR spectroscopy.  

PubMed

White spruce is an important commercial species for reforestation. The success in its propagation through somatic embryogenesis is well documented; however the physiological processes involved are poorly understood and remain unoptimized. The variable quality embryos generated in vitro from the same genotype suggest control at the protein and metabolite level. In order to probe metabolic changes, we have conducted a "metabolic footprinting" study, whereby culture media from growing cells was quantitatively analyzed to determine which metabolites were consumed and excreted. Such experiments are advantageous in that there is no need to quench cellular metabolism or extract intracellular metabolites through time-consuming protocols. In this paper we demonstrate the application of the footprinting assay to somatic embryo cells of white spruce (Picea glauca) using 1D (1)H NMR spectroscopy. We have surveyed embryogenesis metabolism in two types of media, maintenance (MN) and maturation (MT). MN medium does not result in shoot apical meristem (SAM) formation, while MT medium induces the necessary changes leading to fully developed somatic embryos. The two types of media were easily distinguished using metabolomics analysis, namely multivariate pattern recognition statistics (orthogonal partial least squares discriminatory analysis). From this analysis, we have identified numerous compounds involved with branched chain amino acid pathways such as valine and isoleucine. These results are explained on the basis of known metabolic pathways implicated in plant and animal developmental processes, and ultimately implicate altered CoA biosynthesis. PMID:19195904

Dowlatabadi, Reza; Weljie, Aalim M; Thorpe, Trevor A; Yeung, Edward C; Vogel, Hans J

2009-05-01

76

High frequency regeneration via direct somatic embryogenesis and efficient Agrobacterium- mediated genetic transformation of tobacco  

PubMed Central

A direct somatic embryogenesis protocol was developed for four cultivars of Nicotiana species, by using leaf disc as an explant. Direct somatic embryogenesis of Nicotiana by using BAP and IAA has not been investigated so far. This method does not require formation of callus tissues which leads to somaclonal variations. The frequency of somatic embryogenesis was strongly influenced by the plant growth hormones. The somatic embryos developing directly from explant tissue were noticed after 6 d of culture. Somatic embryogenesis of a high frequency (87–96%) was observed in cultures of the all four genotypes (Nicotiana tabacum, N. benthamiyana, N. xanthi, N. t cv petihavana). The results showed that the best medium for direct somatic embryogenesis was MS supplemented with 2.5 mg/l, 0.2 mg/l IAA and 2% sucrose. Subculture of somatic embryos onto hormone free MS medium resulted in their conversion into plants for all genotypes. About 95% of the regenerated somatic embryos germinated into complete plantlets. The plants showed morphological and growth characteristics similar to those of seed-derived plants. Explants were transformed using Agrobacterium tumifacious LBA4404 plasmid pCAMBIA1301 harboring the GUS gene. The regenerated transgenic plants were confirmed by PCR analysis and histochemical GUS assay. The transformation efficiency obtained by using the Agrobacterium- mediated transformation was more than 95%. This method takes 6 wk to accomplish complete transgenic plants through direct somatic embryogenesis. The transgenic plantlets were acclimatized successfully with 98% survival in greenhouse and they showed normal morphological characteristics and were fertile. The regeneration and transformation method described herein is very simple, highly efficient and fast for the introduction of any foreign gene directly in tobacco through direct somatic embryogenesis. PMID:23518589

Pathi, Krishna Mohan; Tula, Suresh; Tuteja, Narendra

2013-01-01

77

High frequency regeneration via direct somatic embryogenesis and efficient Agrobacterium-mediated genetic transformation of tobacco.  

PubMed

A direct somatic embryogenesis protocol was developed for four cultivars of Nicotiana species, by using leaf disc as an explant. Direct somatic embryogenesis of Nicotiana by using BAP and IAA has not been investigated so far. This method does not require formation of callus tissues which leads to somaclonal variations. The frequency of somatic embryogenesis was strongly influenced by the plant growth hormones. The somatic embryos developing directly from explant tissue were noticed after 6 d of culture. Somatic embryogenesis of a high frequency (87-96%) was observed in cultures of the all four genotypes (Nicotiana tabacum, N. benthamiyana, N. xanthi, N. t cv petihavana). The results showed that the best medium for direct somatic embryogenesis was MS supplemented with 2.5 mg/l, 0.2 mg/l IAA and 2% sucrose. Subculture of somatic embryos onto hormone free MS medium resulted in their conversion into plants for all genotypes. About 95% of the regenerated somatic embryos germinated into complete plantlets. The plants showed morphological and growth characteristics similar to those of seed-derived plants. Explants were transformed using Agrobacterium tumifacious LBA4404 plasmid pCAMBIA1301 harboring the GUS gene. The regenerated transgenic plants were confirmed by PCR analysis and histochemical GUS assay. The transformation efficiency obtained by using the Agrobacterium- mediated transformation was more than 95%. This method takes 6 wk to accomplish complete transgenic plants through direct somatic embryogenesis. The transgenic plantlets were acclimatized successfully with 98% survival in greenhouse and they showed normal morphological characteristics and were fertile. The regeneration and transformation method described herein is very simple, highly efficient and fast for the introduction of any foreign gene directly in tobacco through direct somatic embryogenesis. PMID:23518589

Pathi, Krishna Mohan; Tula, Suresh; Tuteja, Narendra

2013-06-01

78

Isolation of two somatic embryogenesis-related genes from orchardgrass ( Dactylis glomerata)  

Microsoft Academic Search

Orchardgrass (Dactylis glomerata L.) leaf segments have a high capacity for direct embryogenesis from mesophyll cells and indirect embryogenesis through callus. Total RNA extracted from leaf cultures of embryogenic and nonembryogenic genotypes were used to generate two differentially expressed cDNA fragments. An embryogenic leaf culture cDNA library was screened with these fragments and two somatic embryogenesis-related genes designated DGE1 and

Krassimira S Alexandrova; B. V Conger

2002-01-01

79

Stimulation of Daucus carota somatic embryogenesis by inhibitors of ethylene synthesis: cobalt and nickel  

Microsoft Academic Search

The effects of Co2+ and Ni2+ on ethylene production and somatic embryogenesis by carrot (Daucus carota L.) cell cultures were studied. At concentrations of 10 µM to 50 µM, CoCl2 effectively inhibited ethylene production by embryogenic cultures and significantly stimulated somatic embryogenesis. The observed increase of embryo number was proportional to the inhibition level of ethylene production. However, CoCl2 had

J. P. Roustan; A. Latche; J. Fallot

1989-01-01

80

Relationship between ploidy variation of citrus calli and competence for somatic embryogenesis.  

PubMed

This study focuses on the relationship between the genetic variation of calli and the competence for somatic embryogenesis in citrus. The DNA content of 35 citrus calli of different genotypes was measured three times by flow cytometry during a period of four years. The results showed that 71.4 % of the genotypes had a progressive increase of varied cells, while those of Page tangelo, Shamouti sweet orange, Russ navel orange and Cleopatra decreased; significant difference in the variation degree (percentages) existed among genotypes. Studies carried out on the induction of somatic embryogenesis revealed that 9 out of the 35 genotypes had still kept the competence of somatic embryogenesis, and the rest 26 had lost the competence. Correlation analysis indicated that there was no significant relationship between the variation degree and the embryogenesis competence r = -0.10 (P < 0.01), neither for the relationship between the subculture duration and the regeneration capacity. PMID:16875323

Zhang, Jun-E; Guo, Wen-Wu; Deng, Xiu-Xin

2006-07-01

81

The somatic embryogenesis and plant regeneration from immature embryo of sweet corn inbred line  

Microsoft Academic Search

Synthetic seed consisting of somatic embryos enclosed in protective coating are a suitable tool for clonal mass propagation of elite plant varieties. The in vitro study was aimed to evaluate the optimizing medium for sweet corn somatic embryogenesis, synthetic seed production which leads to increasing germination and seed viability percentage. The in vitro study was aimed to evaluate the optimizing

Pitipong Thobunluepop

2009-01-01

82

Improvements in somatic embryogenesis protocol in Feijoa ( Acca sellowiana (Berg) Burret): Induction, conversion and synthetic seeds  

Microsoft Academic Search

Pineapple guava (Acca sellowiana) syn. Feijoa sellowiana, a Brazilian indigenous Myrtaceae is under domestication in South Brazil. Previous works showed that this species is responsive to somatic embryogenesis and recalcitrant to conventional methods of clonal propagation. In the present work it was evaluated the role of components of culture medium in the induction and development of somatic embryos. The technology

Gabriela Claudia Cangahuala-Inocente; Lírio Luiz Dal Vesco; Douglas Steinmacher; Antonio Carlos Torres; Miguel Pedro Guerra

2007-01-01

83

Inheritance of somatic embryogenesis and organ regeneration from immature embryo cultures of winter wheat  

Microsoft Academic Search

Diallel analyses of F1 and reciprocal crosses among five winter wheat lines show that additive, non-additive, and cytoplasmic genetic effects were significant in the genetic control of somatic embryogenesis, shoot, and root induction frequencies as well as in numbers of somatic embryos, shoots, and roots. However, additive genetic effect appears to be most important since, in most cases a larger

G. Ou; W. C. Wang; H. T. Nguyen

1989-01-01

84

Improved efficiency of somatic embryogenesis from zygotic embryos in Hyoscyamus niger by seed water-soaking  

Microsoft Academic Search

We describe an efficient procedure to obtain somatic embryos from mature zygotic embryos of Hyoscyamus niger (black henbane). It has several advantages over previous regeneration methods, which are: the use of mature seeds, an average 80% somatic embryogenesis rate and a high (eight-fold higher than the control) plant regeneration frequency. The critical step in this protocol was soaking of the

Shanjun Tu; R. S. Sangwan; B. S. Sangwan-Norreel

2005-01-01

85

[Improved protoplast-derived plants of Astragalus adsurgens through somatic embryogenesis].  

PubMed

Embryogenic callus was obtained only from hypocotyl explants of Astragalus adsurgens and light inhibited the formation of embryogenic callus. A high yield (1.2 x 10(6)/g F. Wt.) of protoplasts with high viability (over 80%) could be isolated from 10-day-old embryogenic callus. Protoplasts were induced to undergo sustained division and to form cell colonies when cultured in agarose-solidified medium (KMP) containing 1/4 strength of mineral salts and supplemented with 1.5 mg/L 2, 4-D, 0.5 mg/L BA and 0.5 mol/L glucose at a plating density of 1.0 x 10(5)mL, where the plating efficinency was 16.8%. Conditioning medium significantly improved the formation of cell colonies. When protoplast-derived colonies were maintained at 4 degrees C for 2 weeks and subsequently transferred onto medium (MS) with 0.1 mg/L NAA and 1.0 mg/L BA, somatic embryogenesis occurred. Frequency of cell colonies producing somatic embryos reached 70%, and the number of somatic embryos per gram cells was over 200. Cultured on hormone-free half-strength MS medium, somatic embryos developed into healthy plantlets with normal chromosome complement. PMID:10883269

Luo, J P; Jia, J F; Gu, Y H; Liu, J

2000-01-01

86

RESEARCH ARTICLE Somatic embryogenesis, rhizogenesis, and morphinan alkaloids production in two species of opium poppy  

E-print Network

A study of somatic embryogenesis and rhizogenesis and their influence on production of morphinan alkaloids on two species of opium poppy is presented. We identified the ratios of auxin and cytokinin that caused somatic embryogenesis and rhizogenesis in hypocotyl and cotyledons of Papaver somniferum album and Papaver orientale splendidissimum. The hypocotyls and cotyledons both show somatic embryogenesis in Papaver somniferum album whereas only the cotyledons were embryogenic in Papaver orientale splendidissimum. For rhizogenesis, the most important response is on the cotyledons and leaves in these two species. Histology showed characteristic stages of somatic embryo: Globular, cotyledonous, and heart cotyledonary. High performance liquid chromatography analysis showed that the roots of both species synthesized codeine, thebaine, and papaverine. Morphine was only detected in aerial parts of Papaver somniferum album. Codeine and thebaine were detected in the rhizogenous but no embryonic callus. These results suggest that root organogenesis is causally related to alkaloid biosynthesis.

My Abdelmajid Kassem; Annie Jacquin

87

Somatic Embryogenesis, Rhizogenesis, and Morphinan Alkaloids Production in Two Species of Opium Poppy.  

PubMed

A study of somatic embryogenesis and rhizogenesis and their influence on production of morphinan alkaloids on two species of opium poppy is presented. We identified the ratios of auxin and cytokinin that caused somatic embryogenesis and rhizogenesis in hypocotyl and cotyledons of Papaver somniferum album and Papaver orientale splendidissimum. The hypocotyls and cotyledons both show somatic embryogenesis in Papaver somniferum album whereas only the cotyledons were embryogenic in Papaver orientale splendidissimum. For rhizogenesis, the most important response is on the cotyledons and leaves in these two species. Histology showed characteristic stages of somatic embryo: Globular, cotyledonous, and heart cotyledonary. High performance liquid chromatography analysis showed that the roots of both species synthesized codeine, thebaine, and papaverine. Morphine was only detected in aerial parts of Papaver somniferum album. Codeine and thebaine were detected in the rhizogenous but no embryonic callus. These results suggest that root organogenesis is causally related to alkaloid biosynthesis. PMID:12488612

Kassem, My Abdelmajid; Jacquin, Annie

2001-01-01

88

Somatic embryogenesis of holm oak ( Quercus ilex L.): ethylene production and polyamine content  

Microsoft Academic Search

The production of ethylene and the endogenous content of polyamines (PAs) have been recorded during the early development,\\u000a maturation and germination of holm oak (Quercus ilex L.) somatic embryos. Ethylene production was high in embryogenic callus, immature somatic embryos and in explants showing\\u000a secondary embryogenesis, while it was lower in mature and germinating somatic embryos. A higher ethylene production was

Pedro V. MauriJose; Jose A. Manzanera

2011-01-01

89

Somatic embryogenesis in white spruce ( Picea glauca ): genetic control in somatic embryos exposed to storage, maturation treatments, germination, and cryopreservation  

Microsoft Academic Search

Genetic controls for growth of embryogenic cultures, storage, maturation treatments, germination and cryopreservation in white spruce somatic embryogenesis (SE) were examined. These SE processes were under genetic control but less strongly so than the initiation phase. For all the SE characters examined, variance due to clones within families was significant and often the largest genetic component of variance. This was

Y. S. Park; S. E. Pond; J. M. Bonga

1994-01-01

90

Ammonium-related metabolic changes affect somatic embryogenesis in pumpkin (Cucurbita pepo L.).  

PubMed

Somatic embryogenesis in pumpkin can be induced on auxin-containing medium and also on hormone-free medium containing 1mM ammonium (NH(4)(+)) as the sole source of nitrogen. Growth of NH(4)(+)-induced embryogenic tissue was slow and caused considerable acidification of the culture medium. Small spherical cells with dense cytoplasma formed proembryogenic cell clusters that could not develop into late stage embryos. Buffering of NH(4)(+) medium with 25mM 2-(N-morpholino)-ethane-sulfonic acid enhanced tissue proliferation, but no further differentiation was observed. Later stage embryos developed only after re-supply of nitrogen in form of nitrate or l-glutamine. Effects of nitrogen status and pH of culture media on ammonium assimilation were analyzed by following the activity of glutamine synthetase (GS) in relation to phenylalanine ammonia-lyase (PAL). Increased activity of GS and PAL in NH(4)(+) induced tissue coincided with significantly higher activity of stress-related enzymes superoxide dismutase (SOD) and soluble peroxidase (POD), indicating oxidative stress response of embryogenic tissue to NH(4)(+) as the sole source of nitrogen. In addition, considerable increase was observed in callose accumulation and esterase activity, the early markers of somatic embryogenesis. Activity of stress-related enzymes decreased after the re-supply of nitrate (20mM) or Gln (10mM) in combination with NH(4)(+) (1mM), which subsequently triggered globular embryo development. Together, these results suggest that stress responses, as affected by nitrogen supply, contribute to the regulation of embryogenic competence in pumpkin. PMID:21807439

Mihaljevi?, Snježana; Radi?, Sandra; Bauer, Nataša; Gari?, Rade; Mihaljevi?, Branka; Horvat, Gordana; Leljak-Levani?, Dunja; Jelaska, Sibila

2011-11-01

91

Callose deposition is required for somatic embryogenesis in plasmolyzed Eleutherococcus senticosus zygotic embryos.  

PubMed

Dynamic changes in callose content, which is deposited as a plant defense response to physiological changes, were analyzed during somatic embryogenesis in Eleutherococcus senticosus zygotic embryos plasmolyzed in 1.0 M mannitol. During plasmolysis, callose deposition was clearly observed inside the plasma membrane of zygotic embryo epidermal cells using confocal laser scanning microscopy. The callose content of zygotic embryos gradually increased between 0 and 12 h plasmolysis and remained stable after 24 h plasmolysis. During eight weeks induction of somatic embryogenesis, the callose content of explants plasmolyzed for 12 h was slightly higher than explants plasmolyzed for 6 or 24 h, with the largest differences observed after 6 weeks culture, which coincided with the maximum callose content and highest number of globular somatic embryos. The highest frequency of somatic embryo formation was observed in explants plasmolyzed for 12 h. The somatic embryo induction rate and number of somatic embryos per explant were markedly different in zygotic embryos pretreated with plasmolysis alone (78.0%, 43 embryos per explant) and those pretreated with plasmolysis and the callose synthase inhibitor 2-deoxy-d-glucose (11.5%, 8 embryos per explant). This study indicates that callose production is required for somatic embryogenesis in plasmolyzed explants. PMID:23203053

Tao, Lei; Yang, Yang; Wang, Qiuyu; You, Xiangling

2012-01-01

92

Cloning, molecular characterization and expression analysis of a SOMATIC EMBRYOGENESIS RECEPTOR - LIKE KINASE gene ( CitSERK1 - like ) in Valencia sweet orange  

Microsoft Academic Search

Somatic embryogenesis receptor-like kinase (SERK) belonging to the receptor-like kinases (RLKs) has been shown to be implicated in somatic embryogenesis (SE). In this study, a somatic embryogenesis receptor-like\\u000a gene CitSERK1-like was cloned and characterized from Citrus sinensis cv. ‘Valencia’, a genotype with high somatic embryogenesis capacity for over 26 years. Fifteen consecutive amino acids in\\u000a putative leucine zipper domain of CitSERK1-like

Xiao-Xia Ge; Gai-En Fan; Li-Jun Chai; Wen-Wu Guo

2010-01-01

93

Somatic embryogenesis and plant regeneration from callus cultures of chickpea ( Cicer arietinum L.)  

Microsoft Academic Search

Somatic embryogenesis and plant regeneration were obtained from immature leaflet callus of chickpea. Numerous globular embryos developed on the surface of callus on Murashige and Skoog's (1962) medium containing 25 M 2,4-dichlorophenoxyacetic acid. These globular embryos differentiated into mature somatic embryos upon removal of 2,4-dichlorophenoxyacetic acid. The maturation of embryos was significantly affected by pH, photoperiod, abscisic acid and genotype.

K. S. Barna; A. K. Wakhlu

1993-01-01

94

Role of exogenous reduced nitrogen and sucrose in rapid high frequency somatic embryogenesis in Medicago sativa  

Microsoft Academic Search

The effect of exogenously supplied reduced nitrogen and sucrose on high-frequency somatic embryogenesis in petiole-derived tissue cultures of a diploid and a tetraploid regenerable clone of Medicago sativa ssp. falcata was investigated. There was an absolute requirement for ammonium during embryo induction and differentiation, with 5mM being the optimum for induction and 10–20 mM the optimum for differentiation of somatic

Eltjo G. M. Meijer; Daniel C. W. Brown

1987-01-01

95

Involvement of Plant Hormones and Plant Growth Regulators on in vitro Somatic Embryogenesis  

Microsoft Academic Search

In spite of the importance attained by somatic embryogenesis and of the many studies that have been conducted on this developmental\\u000a process, there are still many aspects that are not fully understood. Among those features, the involvement of plant hormones\\u000a and plant growth regulators on deTermining the conversion of somatic onto embryogenic tissues, and on allowing progression\\u000a and maturation of

Víctor M. Jiménez

2005-01-01

96

Elimination of Grapevine fanleaf virus from three Vitis vinifera cultivars by somatic embryogenesis  

Microsoft Academic Search

Indirect somatic embryogenesis was tested as a method for eradication of Grapevine fanleaf virus (GFLV) in three grapevine cultivars. Reverse transcriptase-polymerase chain reaction for GFLV detection was performed on\\u000a tissues sampled at various steps of the embryogenic process: flower explants, embryogenic and non-embryogenic calli, single\\u000a somatic embryos and regenerated plants. The virus was detected in all tested anthers and ovaries,

Giorgio Gambino; Daniele Di Matteo; Ivana Gribaudo

2009-01-01

97

Extracts of Marine cyanobacteria stimulated somatic embryogenesis of Daucus carota L  

Microsoft Academic Search

Twenty five strains of marine cyanobacteria were screened for their ability to promote carrot somatic embryogenesis. Hot water extracts prepared from 21 of these strains promoted plantlet formation. Extracts from four strains increased plantlet numbers to an average of over 3.7-fold. Dialysates and nondialysates of each of these extracts also increased plantlet formation. For extracts from filamentous cyanobacteria, Nostoc sp.

Hitoshi Wake; Hironori Umetsu; Yoshihiro Ozeki; Koichiro Shimomura; Tadashi Matsunaga

1991-01-01

98

Somatic embryogenesis and organogenesis from cryopreserved shoot tips of Lilium Oriental hybrid ‘Siberia’  

Technology Transfer Automated Retrieval System (TEKTRAN)

Somatic embryogenesis and organogenesis were achieved from cryopreserved shoot tips of Lilium Oriental hybrid ‘Siberia’. Shoot tips (1.5-2 mm) were excised from adventitious shoots that were regenerated from basal leaf segments. Precultured shoot tips were then treated with MS containing 0.4 M sucro...

99

Regeneration of different Cyclamen species via somatic embryogenesis from callus, suspension cultures and protoplasts  

Microsoft Academic Search

The present study is the first report of the establishment of embryogenic callus cultures from seedling tissue, the regeneration of plants via somatic embryogenesis and the development of a regeneration system from protoplast to plant, using three wild species of Cyclamen, Cyclamen graecum Link, Cyclamen mirabile Hildebrand, Cyclamen trochopteranthum Schwarz (syn. Cyclamen alpinum hort. Dammann ex Sprenger). The ability to

Anika Nadja Sabine Prange; Melanie Bartsch; Margrethe Serek; Traud Winkelmann

2010-01-01

100

The effectiveness of various nitrogen sources in white spruce [ Picea glauca (Moench) Voss] somatic embryogenesis  

Microsoft Academic Search

The effects of glutamine-based dipeptides, glutamine and casein hydrolysate, as well as the deletion of organic nitrogen, were investigated during white spruce [Picea glauca (Moench) Voss] somatic embryogenesis. There were no differences in the fresh weight increase of the tissue masses grown on initiation medium with different combinations of organic nitrogen. This was also the case for subsequent growth on

J. D. Barrett; Y. S. Park; J. M. Bonga

1997-01-01

101

Research note Putrescine enhances somatic embryogenesis and plant regeneration in upland  

E-print Network

significantly lower for these lines as compared to the standard cultivar for cotton transformation, `Coker 312Research note Putrescine enhances somatic embryogenesis and plant regeneration in upland cotton been achieved in several cotton lines (Gossypium hirsutum L.) from the Georgia and Pee Dee germplasm

Chee, Peng W.

102

Somatic embryogenesis from shoot tip and immature inflorescence of Phoenix dactylifera cv. Barhee  

Microsoft Academic Search

Summary  A method of clonal propagation via somatic embryogenesis of date palm, cultivar Barhee, which has potential for large scale commercial application as well as for developmental studies on embryos is described. Cultures were initiated from shoot tip and immature inflorescence explants, both of which were capable of development into embryogenic callus. When the embryogenic callus was cultured in liquid suspension

Shyamala Bhaskaran; Roberta H. Smith

1992-01-01

103

Alfalfa embryo production in airlift vessels via direct somatic embryogenesis  

Microsoft Academic Search

A procedure for the development of alfalfa (Medicago falcata L.) somatic embryos to the torpedo stage in air-lift vessels is described. Embryos were initiated from chopped leaf explants and were formed by direct somatic embryogensis. The system produced a high number of torpedo stage embryos. The effect of various inoculation densities on embryo development was studied. A procedure for the

Alexander I. Kuklin; Plamen D. Denchev; Atanas I. Atanassov; Alan H. Scragg

1994-01-01

104

Assessment of ploidy stability of the somatic embryogenesis process in Quercus suber L. using flow cytometry.  

PubMed

Flow cytometry analyses were used to verify the ploidy stability of Quercus suber L. somatic embryogenesis process. Leaf explants of two adult cork oak trees (QsG0 and QsG5) of the North of Portugal were inoculated on MS medium with 2,4-D and zeatin. After 3 months, calluses with embryogenic structures were isolated and transferred to fresh MS medium without growth regulators and somatic embryo evolution was followed. Morphologically normal somatic embryos (with two cotyledons) and abnormal somatic embryos (with one or three cotyledons) were used in this assay. Flow cytometry combined with propidium iodide staining was employed to estimate DNA ploidy levels and nuclear DNA content of somatic embryos and leaves from mother plants. No significant differences (P< or =0.05) were detected among embryos, and between the embryos and the mother plants. Also, after conversion of these embryos, no significant morphological differences were observed among the somatic embryo-derived plants. These results and further studies using converted plantlet leaves and embryogenic callus tissue indicate that embryo cultures and converted plantlets were stable with regard to ploidy level. As no major somaclonal variation was detected our primary goal of "true-to-type" propagation of cork oak using somatic embryogenesis was assured at this level. The estimation of the 2C nuclear DNA content for this species is similar to the previously obtained value. PMID:15744492

Loureiro, J; Pinto, G; Lopes, T; Dolezel, J; Santos, C

2005-08-01

105

Propagation of Coriandrum sativum L. through somatic embryogenesis.  

PubMed

A highly embryogenic callus was obtained from hypocotyl segments of Coriandrum sativum L. when cultured in the medium consisting of MS + H vitamins (MSH). Induction of somatic embryos required 2,4-dichlorophenoxyacetic acid or napthalene acetic acid. Germination of fully developed embryos was accomplished by subculture on half strength MSH medium containing benzylamino purine 0.05 mg/L. Plantlets developed from somatic embryos were transferred to soil and were successfully flowered. PMID:11491588

Stephan, R; Jayabalan, N

2001-04-01

106

Establishment of embryonic shoot–root axis is involved in auxin and cytokinin response during Arabidopsis somatic embryogenesis  

PubMed Central

Auxin and cytokinin signaling participates in regulating a large spectrum of developmental and physiological processes in plants. The shoots and roots of plants have specific and sometimes even contrary responses to these hormones. Recent studies have clearly shown that establishing the spatiotemporal distribution of auxin and cytokinin response signals is central for the control of shoot apical meristem (SAM) induction in cultured tissues. However, little is known about the role of these hormones in root apical meristem (RAM) initiation. Here, we found that the expression patterns of several regulatory genes critical for RAM formation were correlated with the establishment of the embryonic root meristem during somatic embryogenesis in Arabidopsis. Interestingly, the early expression of the WUS-RELATED HOMEOBOX 5 (WOX5) and WUSCHEL genes was induced and was nearly overlapped within the embryonic callus when somatic embryos (SEs) could not be identified morphologically. Their correct expression was essential for RAM and SAM initiation and embryonic shoot–root axis establishment. Furthermore, we analyzed the auxin and cytokinin response during SE initiation. Notably, cytokinin response signals were detected in specific regions that were correlated with induced WOX5 expression and subsequent SE formation. Overexpression of the ARABIDOPSIS RESPONSE REGULATOR genes ARR7 and ARR15 (feedback repressors of cytokinin signaling), disturbed RAM initiation and SE induction. These results provide new information on auxin and cytokinin-regulated apical–basal polarity formation of shoot–root axis during somatic embryogenesis. PMID:25642237

Su, Ying Hua; Liu, Yu Bo; Bai, Bo; Zhang, Xian Sheng

2015-01-01

107

Direct somatic embryogenesis from protoplasts of Citrus mitis Blanco.  

PubMed

Protoplasts isolated from embryogenic suspension cultures of Citrus mitis were cultured in a medium without any plant growth substances. Somatic embryos developed directly from protoplasts without an obvious intervening callus phase. As many as 1,800 somatic embryos developed from 4 ml of protoplast suspension (density 2×10(6)/ml) cultured for 35 days. Upon transferring the embryoids to medium with 1 mgl(-1) GA3, they developed into plant-lets. Rooted plantlets were obtained in 3 months after protoplast isolation. PMID:24240259

Sim, G E; Loh, C S; Goh, C J

1988-10-01

108

Regeneration of Solanum nigrum by Somatic Embryogenesis, Involving Frog Egg-Like Body, a Novel Structure  

PubMed Central

A new protocol was established for the regeneration of Solanum nigrum by frog egg-like bodies (FELBs), which are novel somatic embryogenesis (SE) structures induced from the root, stem, and leaf explants. The root, stem, and leaf explants (93.33%, 85.10%, and 100.00%, respectively) were induced to form special embryonic calli on Murashige and Skoog (MS) medium containing 1.0 mg/L 2,4-dichlorophenoxyacetic acid, under dark condition. Further, special embryonic calli from the root, stem, and leaf explants (86.97%, 83.30%, and 99.47%, respectively) were developed into FELBs. Plantlets of FELBs from the three explants were induced in vitro on MS medium supplemented with 5.0 mg/L 6-benzylaminopurine and 0.1 mg/L gibberellic acid, and 100.00% plantlet induction rates were noted. However, plantlet induction in vivo on MS medium supplemented with 20 mg/L thidiazuron showed rates of 38.63%, 15.63%, and 61.30% for the root, stem, and leaf explants, respectively, which were lower than those of the in vitro culture. Morphological and histological analyses of FELBs at different development stages revealed that they are a novel type of SE structure that developed from the mesophyll (leaf) or cortex (stem and root) cells of S. nigrum. PMID:24896090

Xu, Kedong; Chang, Yunxia; Liu, Kun; Wang, Feige; Liu, Zhongyuan; Zhang, Ting; Li, Tong; Zhang, Yi; Zhang, Fuli; Zhang, Ju; Wang, Yan; Niu, Wei; Jia, Shuzhao; Xie, Hengchang; Tan, Guangxuan; Li, Chengwei

2014-01-01

109

Role of genetic background in somatic embryogenesis in Medicago  

Microsoft Academic Search

Seventy-six cultivars of alfalfa (Medicago sativa L., M. falcata L. and M. varia Martyn) were tested in vitro for their capacity to produce callus and somatic embryos. A three-step media protocol was used to survey the response of the cotyledons and hypocotyl of each genotype while the epicotyl region was conserved in order to recover highly responding genotypes. The best

Daniel C. W. Brown; Atanas Atanassov

1985-01-01

110

Plant CellReports (1992)11:122-125 Repetitive somatic embryogenesis from peanut cultures in liquid medium  

E-print Network

Plant CellReports (1992)11:122-125 Repetitive somatic embryogenesis from peanut cultures in liquid. A regenerationsystembasedon repetitive somaticembryogenesiswasdevelopedfor peanut(Arachis hypogaeaL.). Embryogenic Plantregenerationfromculturedtissuesof peanut hasbeenreportedsporadicallyfor nearly 15years. Most of the earlier reports described

Parrott, Wayne

111

Developmental Localization and Methylesterification of Pectin Epitopes during Somatic Embryogenesis of Banana (Musa spp. AAA)  

PubMed Central

Background The plant cell walls play an important role in somatic embryogenesis and plant development. Pectins are major chemical components of primary cell walls while homogalacturonan (HG) is the most abundant pectin polysaccharide. Developmental regulation of HG methyl-esterification degree is important for cell adhesion, division and expansion, and in general for proper organ and plant development. Methodology/Principal Findings Developmental localization of pectic homogalacturonan (HG) epitopes and the (1?4)-?-D-galactan epitope of rhamnogalacturonan I (RG-I) and degree of pectin methyl-esterification (DM) were studied during somatic embryogenesis of banana (Musa spp. AAA). Histological analysis documented all major developmental stages including embryogenic cells (ECs), pre-globular, globular, pear-shaped and cotyledonary somatic embryos. Histochemical staining of extracellularly secreted pectins with ruthenium red showed the most intense staining at the surface of pre-globular, globular and pear-shaped somatic embryos. Biochemical analysis revealed developmental regulation of galacturonic acid content and DM in diverse embryogenic stages. Immunodots and immunolabeling on tissue sections revealed developmental regulation of highly methyl-esterified HG epitopes recognized by JIM7 and LM20 antibodies during somatic embryogenesis. Cell walls of pre-globular/globular and late-stage embryos contained both low methyl-esterified HG epitopes as well as partially and highly methyl-esterified ones. Extracellular matrix which covered surface of early developing embryos contained pectin epitopes recognized by 2F4, LM18, JIM5, JIM7 and LM5 antibodies. De-esterification of cell wall pectins by NaOH caused a decrease or an elimination of immunolabeling in the case of highly methyl-esterified HG epitopes. However, immunolabeling of some low methyl-esterified epitopes appeared stronger after this base treatment. Conclusions/Significance These data suggest that both low- and highly-methyl-esterified HG epitopes are developmentally regulated in diverse embryogenic stages during somatic embryogenesis. This study provides new information about pectin composition, HG methyl-esterification and developmental localization of pectin epitopes during somatic embryogenesis of banana. PMID:21826225

Xu, Chunxiang; Zhao, Lu; Pan, Xiao; Šamaj, Jozef

2011-01-01

112

Microarray Analysis of Siberian Ginseng Cyclic Somatic Embryogenesis Culture Systems Provides Insight into Molecular Mechanisms of Embryogenic Cell Cluster Generation  

PubMed Central

Four systems of cyclic somatic embryogenesis of Siberian ginseng (Eleutherococcus senticosus Maxim) were used to study the mechanism of embryonic cell cluster generation. The first, direct somatic embryo induction (DSEI), generates secondary embryos directly from the primary somatic embryos; the second, direct embryogenic cell cluster induction (DEC)), induces embryogenic cell clusters directly from somatic embryos in agar medium. Subsequently, we found that when DEC-derived somatic embryos are transferred to suspension culture or a bioreactor culture, only somatic embryos are induced, and embryogenic cell clusters cannot form. Therefore, these new lines were named DEC cultured by liquid medium (ECS) and DEC cultured by bioreactor (ECB), respectively. Transmission electron microscopy showed that DEC epidermal cells contained a variety of inclusions, distinct from other lines. A cDNA library of DEC was constructed, and 1,948 gene clusters were obtained and used as probes. RNA was prepared from somatic embryos from each of the four lines and hybridized to a microarray. In DEC, 7 genes were specifically upregulated compared with the other three lines, and 4 genes were downregulated. EsXTH1 and EsPLT1, which were among the genes upregulated in DEC, were cloned using the rapid amplification of cDNA ends (RACE). Real-time quantitative PCR showed EsXTH1 was more highly expressed in DEC than in other lines throughout the culture cycle, and EsPLT1 expression in DEC increased as culture duration increased, but remained at a low expression level in other lines. These results suggest that EsXTH1 and EsPLT1 may be the essential genes that play important roles during the induction of embryogenic cell clusters. PMID:24743225

Zhou, Chenguang; Liu, Likun; Li, Chenghao

2014-01-01

113

Somatic embryogenesis on Thin Cell Layers of a C 4 species, Digitaria sanguinalis (L.) Scop  

Microsoft Academic Search

Somatic embryogenesis was obtained from transverse thin cell layers (tTCLs) of Digitaria sanguinalis. tTCLs (0.2 - 0.4mm thick,\\u000a 1mm in diameter) were excised from 4-week-old seedlings and placed onto Murashige and Skoog media supplemented with a varying\\u000a concentration of 2,4-dichlorophenoxyacetic acid (2,4-D) (from 1 µM to 100 µM) and sucrose (from 3% to 24%). Somatic embryos\\u000a were obtained in the

Bui Van Le; Do My Nghieng Thao; C. Gendy; J. Vidal; K. Tran Thanh Van

1997-01-01

114

Somatic embryogenesis and plant regeneration in Cedrela fissilis  

Microsoft Academic Search

Somatic embryos were obtained from immature zygotic embryos of Cedrela fissilis Well. (Meliaceae), after a culture period of 12 months, with regular subcultures every 6–8 weeks. Callus was developed on explants in 2 months\\u000a on Murashige and Skoog (MS) medium containing 2,4 dichlorophenoxyacetic acid (2,4-D) or picloram (PIC). When the calli were\\u000a transferred to fresh medium, embryogenic tissue appeared on

S. Vila; A. Gonzalez; H. Rey; L. Mroginski

2009-01-01

115

Screening of diploid Medicago sativa germplasm for somatic embryogenesis  

Microsoft Academic Search

Nineteen accessions of diploid Medicago sativa L. belonging to the four subspecies sativa, caerula, falcata and xvaria were screened for their ability to produce somatic embryos on hypocotyl-derived callus. Two medium protocols were used in this study, a three-step sequence with exposure of the callus cultures to a high 2,4-D concentration and a two-step sequence without exposure to a high

Eltjo G. M. Meijer; Daniel C. W. Brown

1985-01-01

116

Screening of diploid Medicago sativa germplasm for somatic embryogenesis.  

PubMed

Nineteen accessions of diploid Medicago sativa L. belonging to the four subspecies sativa, caerula, falcata and xvaria were screened for their ability to produce somatic embryos on hypocotyl-derived callus. Two medium protocols were used in this study, a three-step sequence with exposure of the callus cultures to a high 2,4-D concentration and a two-step sequence without exposure to a high 2,4-D concentration. Considerable variation for callus proliferation was observed. In general, the diploid M. sativa accessions showed poor regenerability and it was not possible to correlate high regeneration frequencies with a particular germplasm source. It was, however, possible to identify regenerable genotypes in all four subspecies. One falcata accession produced somatic embryos on the callus induction media at high frequencies. This response was also obtained with a few genotypes from one xvaria accession. All regenerable plants were maintained as shoot cultures and were able to form somatic embryos on petiole-derived calli. PMID:24253990

Meijer, E G; Brown, D C

1985-10-01

117

Plant regeneration from protoplasts of Musa acuminata cv. Mas (AA) via somatic embryogenesis  

Microsoft Academic Search

A protocol for plant regeneration from protoplasts of Musa acuminata cv. Mas (AA) via somatic embryogenesis was developed. Viable protoplasts were isolated from embryogenic cell suspensions\\u000a at a yield of 1.2 × 107 protoplasts\\/ml packed cell volume (PCV). Liquid and feeder layer culture systems with medium-A and medium-B were used for\\u000a protoplast culture. In liquid culture system, medium-B was more efficient for

Wang Xiao; Xue-Lin Huang; Xia Huang; Ya-Ping Chen; Xue-Mei Dai; Jie-Tang Zhao

2007-01-01

118

Callus culture of Coronilla varia L. (crownvetch): plant regeneration through somatic embryogenesis  

Microsoft Academic Search

Callus culture and plant regeneration through somatic embryogenesis have been obtained in Coronilla varia. Media used were UM (25) supplemented with 2 mg\\/l 2,4-D followed by subculture on MS (18) containing 1 mg\\/l 2-iP and 0.1 mg\\/l IAA. Embryoids developed into complete plantlets on filter paper saturated with hormone-free MS medium.

Domenico Mariotti; Sergio Arcioni

1983-01-01

119

Somatic embryogenesis induction in leaves and petioles of a mature wild olive  

Microsoft Academic Search

We describe a protocol for somatic embryogenesis (SE) induction from an adult wild olive tree (Olea\\u000a europaea ssp. europaea var. sylvestris. The protocol used confirms for the first time that there is no need to use juvenile or rejuvenated material for SE induction.\\u000a For SE induction, petiole and leaf (proximal, intermediary and distal zones) explants were grown on Murashige and

Ana Margarida Capelo; Sónia Silva; Gina Brito; Conceiçăo Santos

2010-01-01

120

Assessment of ploidy stability of the somatic embryogenesis process in Quercus suber L. using flow cytometry  

Microsoft Academic Search

Flow cytometry analyses were used to verify the ploidy stability of Quercus suber L. somatic embryogenesis process. Leaf explants of two adult cork oak trees (QsG0 and QsG5) of the North of Portugal were inoculated on MS medium with 2,4-D and zeatin. After 3 months, calluses with embryogenic structures were isolated and transferred to fresh MS medium without growth regulators and

J. Loureiro; G. Pinto; T. Lopes; J. Doležel; C. Santos

2005-01-01

121

Somatic embryogenesis and plant regeneration from immature embryos of western larch  

Microsoft Academic Search

Somatic embryogenesis was initiated from immature embryos of western larch (Larix occidentalis Nutt.) on media containing 2,4-dichlorophenoxyacetic acid and N6- benzyladenine. The effects of explant type and ammonium nitrate and glutamine concentrations on initiation were tested. Although 21–93% of explants rendered cultures in various experiments, only 3% yielded sustainable embryogenic lines. Excised embryos at the early cotyledonary stage were optimal

R. Gail Thompson; Patrick von Aderkas

1992-01-01

122

Genotype-specific normalization of soybean somatic embryogenesis through the use of an ethylene inhibitor  

Microsoft Academic Search

The effect of ethylene on somatic embryogenesis from cotyledons of soybean (Glycine max) cultivars `Bragg', `IAS-5', and `RS-7' was studied through the application of silver nitrate or aminoethoxyvinylglycine.\\u000a The addition of these chemicals to the induction medium had no effect on embryo induction, in spite of aminoethoxyvinylglycine\\u000a having decreased ethylene production and silver nitrate enhancing it. However, subsequent histodif-ferentiation and

K. G. B. Santos; E. Mundstock; M. H. Bodanese-Zanettini

1997-01-01

123

Induction of somatic embryogenesis and embryo development in Rumex acetosella L  

Microsoft Academic Search

Axillary buds of the dioecious plant Rumex acetosella L. were isolated and cultured in vitro. The callus tissue which developed at the basal parts of the explants displayed a high capacity for shoot formation. This morphogenetic pattern was predominant on Murashige and Skoog (MS) medium supplemented with 2% sucrose, 2.2 mgl-1 benzylaminopurine and 0.17 mgl-1 indole-3-acetic acid. Somatic embryogenesis was

Ljubinka ?ulafi?; SneŽana Budimir; Radmila Vuji?i?; Mirjana Neškovi?

1987-01-01

124

Somatic embryogenesis in Arabidopsis thaliana is facilitated by mutations in genes repressing meristematic cell divisions.  

PubMed Central

Embryogenesis in plants can commence from cells other than the fertilized egg cell. Embryogenesis initiated from somatic cells in vitro is an attractive system for studying early embryonic stages when they are accessible to experimental manipulation. Somatic embryogenesis in Arabidopsis offers the additional advantage that many zygotic embryo mutants can be studied under in vitro conditions. Two systems are available. The first employs immature zygotic embryos as starting material, yielding continuously growing embryogenic cultures in liquid medium. This is possible in at least 11 ecotypes. A second, more efficient and reproducible system, employing the primordia timing mutant (pt allelic to hpt, cop2, and amp1), was established. A significant advantage of the pt mutant is that intact seeds, germinated in 2,4-dichlorophenoxyacetic acid (2, 4-D) containing liquid medium, give rise to stable embryonic cell cultures, circumventing tedious hand dissection of immature zygotic embryos. pt zygotic embryos are first distinguishable from wild type at early heart stage by a broader embryonic shoot apical meristem (SAM). In culture, embryogenic clusters originate from the enlarged SAMs. pt somatic embryos had all characteristic embryo pattern elements seen in zygotic embryos, but with higher and more variable numbers of cells. Embryogenic cell cultures were also established from seedling, of other mutants with enlarged SAMs, such as clavata (clv). pt clv double mutants showed additive effects on SAM size and an even higher frequency of seedlings producing embryogenic cell lines. pt clv double mutant plants had very short fasciated inflorescence stems and additive effects on the number of rosette leaves. This suggests that the PT and CLV genes act in independent pathways that control SAM size. An increased population of noncommitted SAM cells may be responsible for facilitated establishment of somatic embryogenesis in Arabidopsis. PMID:9611173

Mordhorst, A P; Voerman, K J; Hartog, M V; Meijer, E A; van Went, J; Koornneef, M; de Vries, S C

1998-01-01

125

Somatic embryogenesis and plant regeneration in cultured immature inflorescences of Setaria italica  

Microsoft Academic Search

Young inflorescence explants of Setaria italica in culture showed high capacity for regenerating plantlets through somatic embryogenesis. Embryogenic callus formation was initiated from the explants cultured on Murashige and Skoog's medium with 2 mg\\/l 2,4-D and 0.2–0.5 mg\\/l KT or BAP, but it was better for the maintenance of embryogenic growth to subculture the calli on the medium with 2,4-D

Zhi-hong Xu; Da-yuan Wang; Li-jun Yang; Zhi-ming Wei

1984-01-01

126

Co-Localization of ?-1,3-Glucanases and Callose During Somatic Embryogenesis in Cichorium  

PubMed Central

During direct somatic embryogenesis in leaves of Cichorium hybrid clone ‘474’, 38 kDa ?-1,3-glucanases are accumulated in the culture medium of the embryogenic hybrid to a higher level when compared with a non-embryogenic cultivar. In the same time, embryogenic cells were surrounded by a cell wall that was characterized by the presence of callose. This callosic deposition disappeared as embryos grew. Callose consisted of ?-1,3-glucan linkages and so represented a possible substrate for ?-1,3-glucanases. Using immunolocalization experiments, we demonstrated that from the three types of callose deposits observed during the culturing of Cichorium leaf explants, only the callose present in the walls surrounding reactivated cells seemed specifically related to somatic embryogenesis. Moreover, callose and the 38-kDa ?-1,3-glucanases were co-localized dispersed throughout the thick and swelled walls of reactivated cells and embryo cell walls. This suggests that callose and ?-1,3-glucanases are implicated in the process of somatic embryogenesis since they were always detected in or quite near embryogenic and embryo cell. This also suggested that ?-1,3-glucanases could be involved in the degradation of this callose. PMID:19517006

Grimault, Valérie; Helleboid, Stéphane; Vasseur, Jacques

2007-01-01

127

Somatic embryogenesis and plant regeneration from leaf tissue of jojoba  

Microsoft Academic Search

A protocol was developed for the induction, maturation and germination of somatic embryos from leaf tissue of jojoba [Simmondsia chinensis (Link) Schneider]. Explants were placed on their adaxial sides in Petri dishes and maintained in darkness on half-strength\\u000a Murashige and Skoog basal medium (MS\\/2). Combinations of 2,4-dichlorophenoxyacetic acid (1.35–4.52 ?M) with 6-benzylaminopurine\\u000a (1.33–4.43?M) and 2 synthetic cytokinins, N-(2-chloro-4pyridyl)-N?-phenylurea (1.21–4.03?M) or

L. Hamama; M. Baaziz; R. Letouzé

2001-01-01

128

Influence of external factors on secondary embryogenesis and germination in somatic embryos from leaves of Quercus suber  

Microsoft Academic Search

Somatic embryogenesis was obtained in cultures of leaves from young seedlings of Quercus suber L. A two-stage process, in which benzyladenine and naphthaleneacetic acid were added first at high and then at low concentrations, was required to initiate the process. Somatic embryos arose when the explants were subsequently placed on medium lacking plant growth regulators. The embryogenic lines remained productive,

Bárbara Fernández-Guijarro; Cristina Celestino; Mariano Toribio

1995-01-01

129

Evaluation of somaclonal variation during somatic embryogenesis of interior spruce ( Picea glauca engelmannii complex) using culture morphology and isozyme analysis  

Microsoft Academic Search

Somaclonal variation during interior spruce (Picea glauca engelmannii complex) somatic embryogenesis was evaluated using culture morphology and isozyme analysis. Genotype-specific abscisic acid-dependent developmental profiles and isozyme patterns were similar for subclone and parent line embryogenic cultures and cotyledonary somatic embryos. Extensive analysis of fifteen hundred subclone embryos of one genotype revealed no isozyme pattern variation. Initiation of embryogenic cultures was

P. Ann K. Eastman; Fiona B. Webster; Jack A. Pitel; Dane R. Roberts

1991-01-01

130

Enhanced somatic embryogenesis by salicylic acid of Astragalus adsurgens Pall.: relationship with H 2O 2 production and H 2O 2-metabolizing enzyme activities  

Microsoft Academic Search

Salicylic acid (SA), when added to the differentiation medium below 200 ?mol\\/l, significantly enhanced somatic embryogenesis in callus culture of Astragalus adsurgens Pall. The highest frequency of somatic embryogenesis occurred at 150 ?mol\\/l SA. Enhanced somatic embryogenesis by SA was accompanied by an increase in the endogenous H2O2 level as compared with controls. This increased endogenous H2O2 level was related

Jian-Ping Luo; Shao-Tong Jiang; Li-Jun Pan

2001-01-01

131

Effect of 2-( n-morpholino)ethanesulfonic acid and myo-inositol on somatic embryogenesis and plant regeneration from zygotic embryos of Hyoscyamus niger L  

Microsoft Academic Search

A rapid and efficient regeneration system via somatic embryogenesis has been developed from zygotic embryos of Hyoscyamus niger (black henbane). The effect of 2-(n-morpholino)ethanesulfonic acid (MES), myo-inositol (MI) and different combinations of them with a number of growth regulators on somatic embryogenesis was evaluated. Maximum frequency of direct somatic embryogenesis and germination (30.6%) was achieved after 2–5 weeks by a

Shanjun Tu; Thiérry Tétu; Rajbir S. Sangwan; Brigitte S. Sangwan-Norreel

1996-01-01

132

Somatic embryogenesis and plant regeneration from immature embryos of western larch.  

PubMed

Somatic embryogenesis was initiated from immature embryos of western larch (Larix occidentalis Nutt.) on media containing 2,4-dichlorophenoxyacetic acid and N6- benzyladenine. The effects of explant type and ammonium nitrate and glutamine concentrations on initiation were tested. Although 21-93% of explants rendered cultures in various experiments, only 3% yielded sustainable embryogenic lines. Excised embryos at the early cotyledonary stage were optimal for initiation. Maturation of somatic embryos was promoted by abscisic acid. Response to abscisic acid concentrations and duration of exposure to abscisic acid varied with genotype. Maximal results were obtained with 0.025 ? M abscisic acid for 1 to 2 weeks followed by individual culture on medium without growth regulators. Mature somatic embryos developed into shoots with roots. Plantlets have been established in peat. PMID:24201537

Thompson, R G; von Aderkas, P

1992-07-01

133

Conifer somatic embryogenesis: improvements by supplementation of medium with oxidation-reduction agents.  

PubMed

A major barrier to the commercialization of somatic embryogenesis technology in loblolly pine (Pinus taeda L.) is recalcitrance of some high-value crosses to initiate embryogenic tissue (ET) and continue early-stage somatic embryo growth. Developing initiation and multiplication media that resemble the seed environment has been shown to decrease this recalcitrance. Glutathione (GSH), glutathione disulfide (GSSG), ascorbic acid and dehydroascorbate analyses were performed weekly throughout the sequence of seed development for female gametophyte and zygotic embryo tissues to determine physiological concentrations. Major differences in stage-specific oxidation-reduction (redox) agents were observed. A simple bioassay was used to evaluate potential growth-promotion of natural and inorganic redox agents added to early-stage somatic embryo growth medium. Compounds showing statistically significant increases in early-stage embryo growth were then tested for the ability to increase initiation of loblolly pine. Low-cost reducing agents sodium dithionite and sodium thiosulfate increased ET initiation for loblolly pine and Douglas fir (Mirb) Franco. Germination medium supplementation with GSSG increased somatic embryo germination. Early-stage somatic embryos grown on medium with or without sodium thiosulfate did not differ in GSH or GSSG content, suggesting that sodium thiosulfate-mediated growth stimulation does not involve GSH or GSSG. We have developed information demonstrating that alteration of the redox environment in vitro can improve ET initiation, early-stage embryo development and somatic embryo germination in loblolly pine. PMID:25716878

Pullman, Gerald S; Zeng, Xiaoyan; Copeland-Kamp, Brandi; Crockett, Jonathan; Lucrezi, Jacob; May, Sheldon W; Bucalo, Kylie

2015-02-01

134

Lodgepole pine: the first evidence of seed-based somatic embryogenesis and the expression of embryogenesis marker genes in shoot bud cultures of adult trees.  

PubMed

Of the various alternatives for cloning elite conifers, somatic embryogenesis (SE) appears to be the best option. In recent years, significant areas of lodgepole pine (Pinus contorta) forest have been devastated by the mountain pine beetle (MPB) in Western Canada. In an attempt to establish an SE propagation system for MPB-resistant lodgepole pine, several families displaying varying levels of resistance were selected for experimentation involving shoot bud and immature seed explants. In bud cultures, eight embryogenic lines were induced from 2 of 15 genotypes following various treatments. Genotype had an important influence on embryogenic culture initiation, and this effect was consistent over time. These lines were identified by microscopic observation and genetic markers. Despite the abundance of early somatic embryos, the cultures have yet to develop into mature embryos. In contrast, immature zygotic embryos (ZEs) cultured from megagametophytes initiated SE at an early dominance stage via nodule-type callus in 1 of 10 genotypes. As part of the study, putative embryogenesis-specific genes, WOX2 (WUSCHELL homeobox 2) and HAP3A, were analyzed in cultures of both shoot bud explants and ZEs. On the basis of these analyses, we postulate that PcHAP3A was expressed mainly in callus and may be involved in cell division, whereas WOX2 was expressed mainly in embryonal mass (EM)-like tissues. The findings from this study, based on molecular assessment, suggest that the cell lines derived from bud cultures were truly EM. Moreover, these experimental observations suggest that PcWOX2 could be used as an early genetic marker to discriminate embryogenic cultures from callus. PMID:20935320

Park, So-Young; Klimaszewska, Krystyna; Park, Ji-Young; Mansfield, Shawn D

2010-11-01

135

A novel regeneration system for a wild passion fruit species ( Passiflora cincinnata Mast.) based on somatic embryogenesis from mature zygotic embryos  

Microsoft Academic Search

The objective of the present work was to induce somatic embryogenesis from zygotic embryos of Passiflora cincinnata Masters. Zygotic embryos formed calli on media with different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and\\u000a 4.5 ?M benzyladenine (BA) after 30 days of in vitro culture. A concentration of 18.1 ?M 2,4-D resulted in the largest number\\u000a of somatic embryos. Embryogenic calli were yellowish and friable,

Maurecilne Lemes da Silva; Daniela Lopes Paim Pinto; Miguel Pedro Guerra; Eny Iochevet Segal Floh; Cláudio Horst Bruckner; Wagner Campos Otoni

2009-01-01

136

Vegetative propagation of Quercus suber L. by somatic embryogenesis. I. Factors affecting the induction in leaves from mature cork oak trees.  

PubMed

Somatic embryogenesis was induced in expanding leaves from epicormic shoots forced to sprout from segments of branches collected from several hundred-year-old cork oak trees. Following a basic protocol previously defined for leaves taken from seedlings of this species, several factors were studied to improve the response. The induction frequency was significantly higher when the length of exposure to growth regulators was increased from 7 to 30 days. The combined application of NAA and BAP was essential for induction. Although both regulators had a very significant influence, their interaction was not significant, suggesting independent roles. Leaf size had a crucial effect, because beyond a certain threshold, embryogenesis could not be obtained. Embryogenic lines were maintained via repetitive embryogenesis on hormone-free medium for more than 2 years. PMID:12789519

Hernández, I; Celestino, C; Toribio, M

2003-04-01

137

THE REGENERATION OF BLACK GRAMA PLANTS VIA SOMATIC EMBRYOGENESIS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Seeds of Bouteloua eropida, (Torr.) Torr. were surface disinfested and germinated on a carbon mineral rich medium. Callus was initiated from embryonic shoots excised from the roots on auxin supplemented medium. After callus multiplication, embryos were induced from callus. They developed into nor...

138

An efficient in vitro system for somatic embryogenesis and podophyllotoxin production in Podophyllum hexandrum Royle.  

PubMed

Podophyllum hexandrum Royle known as Indian mayapple is an important medicinal plant found only in higher altitudes (2,700 to 4,200 m) of the Himalayas. The highly valued anticancer drug Podophyllotoxin is obtained from the roots of this plant. Due to over exploitation, this endemic plant species is on the verge of extinction. In vitro culture for efficient regeneration and the production of podophyllotoxin is an important research priority for this plant. Hence, in the present study, an efficient plant regeneration system for mass multiplication through somatic embryogenesis was developed. We have screened P. hexandrum seeds collected from three different regions in the Himalayas to find their regenerative potentials. These variants showed variation in germination percentage as well as somatic embryogenic frequency. The seeds collected from the Milam area of Pithoragarh district showed better germination response (99.3%) on Murashige and Skoog (MS) medium fortified with Gibberellic acid (GA3 [5 mg/l]) and higher direct somatic embryogenic frequency (89.6%). Maximum production of embryogenic callus (1.2 g fresh weight [FW]) was obtained when cotyledons containing the direct somatic embryo clusters were cultured in MS medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D [1.5 mg/l]) after 4 week of culture in complete darkness. In the present investigation, somatic embryogenesis was accomplished either by direct organogenesis or callus mediated pathways. The latter method resulted in a higher frequency of somatic embryo induction in hormone-free MS medium yielding 47.7 embryos/50 mg of embryogenic callus and subsequent germination in MS medium supplemented with GA3 (5 mg/l). Seventy-nine percent of embryos attained complete maturity and germinated into normal plants with well-developed roots. Systematic histological analysis revealed the origin of somatic embryo and their ontogenesis. The higher level of podophyllotoxin (1.8 mg/g dry weight [DW]) was recorded in germinated somatic embryos when compared to field grown plants. The present system can be widely used for mass propagation, transgenic recovery, and podophyllotoxin production for commercial utilization. PMID:24633328

Rajesh, Manoharan; Sivanandhan, Ganeshan; Jeyaraj, Murugaraj; Chackravarthy, Rajan; Manickavasagam, Markandan; Selvaraj, N; Ganapathi, Andy

2014-09-01

139

Somatic embryogenesis and plant regeneration in zygotic embryos of Trifolium nigrescens (Viv.)  

Microsoft Academic Search

This study developed a plant regeneration protocol for Trifolium nigrescens (Viv.) via somatic embryogenesis (SE). Immature zygotic embryos at torpedo (TsE) and cotyledonary (CsE) stage were cultured on media\\u000a with different auxins and cytokinins at different concentrations. The cultural requirements for SE differed between the explants\\u000a used: the addition of 6-furfurylaminopurine (kinetin) or N6-[2-isopentenyl]-adenine (2iP) along with 2,4-dihydrophenoxyacetic acid (2,4-D)

Robert Konieczny; Maria Pilarska; Monika Tuleja; Terezia Salaj; Tomasz Ilnicki

2010-01-01

140

Somatic embryogenesis and plant regeneration from immature embryos of five families of Quercus acutissima  

Microsoft Academic Search

Immature embryos of sawtooth oak (Quercus acutissima Carruth.) were obtained from five seed families and cultured on modified Murashige and Skoog nutrient medium containing 1\\u000a g\\/l l-glutamine and 5 mM proline and supplemented with 1.0 mg\\/l indole-3-butyric acid and 1.0 mg\\/l 6-benzylaminopurine. The frequency of somatic embryogenesis\\u000a from immature embryos was a function of the collection date and seed family.

Y. W. Kim; Y. Youn; E. R. Noh; J. C. Kim

1997-01-01

141

The role of nickel on somatic embryogenesis in Setaria italica L. in vitro  

Microsoft Academic Search

Nickel (0.13, 0.25, 0.5, 1.0 and 1.5 mg\\/l) increased the efficiency of somatic embryogenesis in leaf base and mesocotyl derived\\u000a calli of Setaria italica. A lower concentration of nickel in the culture media promoted long-term maintenance of embryogenic\\u000a calli that regenerated into plantlets. The plants obtained from embryogenic calli grown on Ni-containing medium showed tolerance\\u000a to nickel. The growth of

G. R. Rout; S. Samantaray; P. Das

1998-01-01

142

Large impact of the apoplast on somatic embryogenesis in Cyclamen persicum offers possibilities for improved developmental control in vitro  

PubMed Central

Background Clonal propagation is highly desired especially for valuable horticultural crops. The method with the potentially highest multiplication rate is regeneration via somatic embryogenesis. However, this mode of propagation is often hampered by the occurrence of developmental aberrations and non-embryogenic callus. Therefore, the developmental process of somatic embryogenesis was analysed in the ornamental crop Cyclamen persicum by expression profiling, comparing different developmental stages of embryogenic cell cultures, zygotic vs. somatic embryos and embryogenic vs. non-embryogenic cell cultures. Results The analysis was based on a cDNA microarray representing 1,216 transcripts and was exemplarily validated by realtime PCR. For this purpose relative transcript abundances of homologues of a putative receptor kinase, two different glutathione S-transferases (GST), a xyloglucan endotransglycosylase (XET) and a peroxidase (POX) were quantitatively measured by realtime PCR for three different comparisons. In total, 417 genes were found to be differentially expressed. Gene Ontology annotation revealed that transcripts coding for enzymes that are active in the extracellular compartment (apoplast) were significantly overrepresented in several comparisons. The expression profiling results are underpinned by thorough histological analyses of somatic and zygotic embryos. Conclusions The putative underlying physiological processes are discussed and hypotheses on improvement of the protocol for in vitro somatic embryogenesis in Cyclamen persicum are deduced. A set of physiological markers is proposed for efficient molecular control of the process of somatic embryogenesis in C. persicum. The general suitability of expression profiling for the development and improvement of micropropagation methods is discussed. PMID:20426818

2010-01-01

143

Dynamics of the concentration of IAA and some of its conjugates during the induction of somatic embryogenesis in Coffea canephora  

PubMed Central

Most of the somatic embryogenesis (SE) process requires the presence, either before or during the embryogenic process, of at least one exogenous auxin. This exogenous auxin induces the presence of endogenous auxins, which appears to be essential for SE induction. We found that during the preincubation period of SE in Coffea canephora, there is an important increase in both free and conjugated indole-3-acetic acid (IAA), as well as indole-3-butyric acid. This increase is accompanied by an increase in the expression of YUCCA (CcYUC), TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1 (CcTAA1), and GRETCHEN HAGEN 3 (GH3) genes. On the other hand, most of the IAA compounds decreased during the induction of SE. The results presented in this research suggest that a balance between free IAA and its amide conjugates is necessary to allow the expression of SE-related genes. PMID:24299659

Ayil-Gutiérrez, Benajmín; Galaz-Ávalos, Rosa María; Peńa-Cabrera, Eduardo; Loyola-Vargas, Victor Manuel

2013-01-01

144

Somatic embryogenesis in cultured immature zygotic embryos and leaf protoplasts of Arabidopsis thaliana ecotypes.  

PubMed

Immature zygotic embryos of six ecotypes (Nd-0, Ler, C24, Col-0, Nossen, Ws-2) of Arabidopsis thaliana (L.) Heynh. were cultured in vitro. The same ecotypes, except Nossen, were used for studies on leaf protoplast culture. Experimental conditions for the induction of somatic embryos were established in both culture systems. In the case of immature zygotic embryos, the parameters investigated were the influence of developmental stage of the explant, the ecotypes used, and various concentrations and combinations of growth regulatory substances (phytohormones). In the ecotype Ler, structures were discovered which were very similar to those found in the early stages of zygotic embryo-genesis: globular structures at the end of a suspensor-like single file of cells were frequently observed. In the case of leaf protoplasts, high efficiencies of colony formation and plant regeneration occurred in Ws-2 and C24. A novel type of cell division pattern was found in Col-0 and C24, again highly reminiscent of the early division patterns in zygotic embryos. Similarities and differences between zygotic and somatic embryogenesis are discussed. PMID:9232908

Luo, Y; Koop, H U

1997-01-01

145

Somatic embryogenesis in Solanum tuberosum from cell suspension cultures: histological analysis and extracellular protein patterns.  

PubMed

An embryogenic cell suspension, continuously grown in Murashige and Skoog (MS) medium with 0.5 mg/L of 2,4-dichlorophenoxyacetic acid, was established from friable callus of Solanum tuberosum internode sections. The cell suspension was predominantly composed of cell masses and free embryogenic cells. When transferred to an auxin-free medium with zeatin, somatic embryos (SEs) developed and converted to complete plants when cultured on solid MS medium without growth regulators. The system produced approximately 600 SEs per 50 mL of medium. In this investigation, accumulation of extracellular proteins (EPs) of different molecular weights were found associated to different phases of the embryogenic process. At the initiation of the cell suspension, cell clusters and free cells present in the culture (phase "A") secreted a 78kDa EP, unique to this phase. In phase "B", which is related to embryonic cell determination process, proteins (7-14kDa) were secreted mainly by embryogenic cells. In phase "C", SEs in different developmental stages secreted protein of 32 kDa, which appeared as a particular feature of the phase. EPs of phase "D", secreted by torpedo and mature embryos, had molecular weights between 20 and 50 kDa. Further studies will be necessary to identify these proteins and link them to previously identified somatic embryogenesis-related proteins. Histological analysis of the potato embryogenesis in liquid media showed unicellular origin of the SE. PMID:15900887

Vargas, Teresa E; De García, Eva; Oropeza, Maira

2005-04-01

146

Influence of low temperature preincubation on somatic embryogenesis and ethylene emanation from orchardgrass leaves  

NASA Technical Reports Server (NTRS)

The objectives of this study were to determine the effects of low temperature (4 degrees C) preincubation on somatic embryogenesis from orchardgrass (Dactylis glomerata L.) leaf cultures and to relate these effects to ethylene emanation during the preincubation and incubation periods. Experiments were also conducted with an ethylene biosynthesis inhibitor aminooxyacetic acid (AOA). Segments from the innermost two leaves were cultured on SH medium with 30 micromoles dicamba at 4 degrees C for 1 to 7 d before transfer to 21 degrees C. Results from a paired design showed that the embryogenic response of leaf segments preincubated at 4 degrees C was equal or superior to nonpreincubated leaves at all time periods. Ethylene emanation was decreased during the low temperature incubation. Transfer of leaf segments from 4 degrees C to 21 degrees C was accompanied by a burst of ethylene which rose to control levels within 30 min. AOA at 20 and 40 micromoles decreased ethylene emanation but did not stimulate the embryogenic response. We conclude that the stimulation of somatic embryogenesis by low temperature is probably due to factors other than suppression of ethylene biosynthesis.

Tomaszewski, Z. Jr; Kuklin, A. I.; Sams, C. E.; Conger, B. V.

1994-01-01

147

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

PubMed

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. PMID:12789520

Hernández, I; Celestino, C; Alegre, J; Toribio, M

2003-04-01

148

Regeneration of Astragalus adsurgens via somatic embryogenesis from cell suspension protoplasts.  

PubMed

Protoplasts from 4-day-old embryogenic cell suspension cultures of Astragalus adsurgens, when cultured in KM8P medium which ammonium concentration was reduced to 2.5 mmol/L and supplemented with 0.5 mg/L NAA, 1.0 mg/L 2, 4-D, 0.7 mg/L BA and 0.4 mol/L glucose, underwent cell sustained divisions and formed cell colonies at a frequency of 16%-20%. Preplasmolysis or low temperature treatment of suspension cells prior to enzyme incubation enhanced colony formation. Following proliferation on MS medium containing 1.0 mg/L 2, 4-D and 0.5 mg/L BA, cell colonies were cultured on MS medium containing 0.1 mg/L NAA and 1.0 mg/L BA, where approximately 40% of colonies produced somatic embryos ranging in number from 20 to 40 per colony. No significant decrease was found in the potential of somatic embryogenesis when protoplast colonies were obtained from long-term cell suspensions. On hormone-free 1/2 MS medium, somatic embryos developed into intact plants, which showed normal morphology and stable chromosome number. PMID:12548868

Luo, J P; Jia, J F; Gu, Y H

1999-12-01

149

Bisphenol A induces otolith malformations during vertebrate embryogenesis  

E-print Network

Bisphenol A induces otolith malformations during vertebrate embryogenesis Gibert et al. Gibert et) #12;RESEARCH ARTICLE Open Access Bisphenol A induces otolith malformations during vertebrate Background: The plastic monomer and plasticizer bisphenol A (BPA), used for manufacturing polycarbonate

Paris-Sud XI, Université de

150

Spruce embryogenesis.  

PubMed

Somatic embryogenesis, the process in which embryos, similar in morphology to their zygotic counterparts, are induced to develop in culture from somatic cells, is a suitable model system for investigating the regulation of embryo development. Through this process, a large number of embryos at defined stages of development can easily be obtained. Somatic embryogenesis in Norway spruce is comprised of a sequence of steps including initiation, proliferation, early embryo formation, embryo maturation, desiccation and germination. To execute this pathway, a number of critical physical and chemical treatments should be applied with proper timing. Embryogenic cell lines of Norway spruce are initiated from zygotic embryos. The cell lines proliferate as proembryogenic masses (PEMs) in the presence of auxin and cytokinin. Early somatic embryos develop from PEMs after withdrawal of auxin and cytokinin. PEM to somatic embryo transition is a key developmental switch that determines the yield and quality of mature somatic embryos. The embryos develop further, to a stage corresponding to late embryogeny, in the presence of abscisic acid. Some cell lines deviate from normal pattern formation exhibiting developmental arrest at certain stages. These arrested cell lines, together with transgenic lines, are valuable tools for studying embryo development. Particle bombardment is routinely used to produce transgenic plants of Norway spruce. PMID:18369995

von Arnold, Sara; Clapham, David

2008-01-01

151

Stimulation of somatic embryogenesis and plant regeneration from anther culture of Vitis vinifera cv. Cabernet-Sauvignon  

Microsoft Academic Search

Somatic embryogenesis and subsequent diploid plants have been obtained from anthers of Vitis vinifera Cabernet-Sauvignon, a cultivar so far considered as recalcitrant to in vitro regeneration. Anthers enclosing microspores near the first pollen mitosis were found to be the most responsive. However, from a practical point of view anther length proved to be an easier criterium for determining the optimal

M. Cl. Mauro; C. Nef; J. Fallot

1986-01-01

152

Induction by thidiazuron of somatic embryogenesis in intact seedlings of peanut  

Microsoft Academic Search

In planta differentiation of somatic embryos was induced in seedlings of peanut (Arachis hypogaea L.) obtained from mature seeds germinated on a medium supplemented with thidiazuron (TDZ: N-phenyl-N1- (1,2,3 thiadiazol-yl)urea). At optimum levels of TDZ (10 µM), all germinating seeds produced embryogenic seedlings, and somatic embryos developed in the apical region and on the surface of cotyledons and hypocotyls. These

Praveen K. Saxena; Kamal A. Malik; R. Gill

1992-01-01

153

High-frequency regeneration via somatic embryogenesis of an elite recalcitrant cotton genotype ( Gossypium hirsutum L.) and efficient Agrobacterium -mediated transformation  

Microsoft Academic Search

A highly efficient and reproducible regeneration system based on somatic embryogenesis in Gossypium hirsutum cv. Narasimha (NM), which has superior fiber qualities and is also used as a female parent in several hybrid cottons, has\\u000a been developed. Embryogenic callus was obtained form both hypocotyls and cotyledonary leaves on Murashige and Skoog (MS) medium\\u000a containing kinetin and 2,4-dichlorophenoxyacetic acid. Somatic embryogenesis

Tanveer Khan; Vanga Siva Reddy; Sadhu Leelavathi

2010-01-01

154

Somatic embryogenesis and plant regeneration from immature embryos of saw palmetto, an important landscape and medicinal plant  

Microsoft Academic Search

Somatic embryogenesis and plant regeneration from immature zygotic embryos was achieved for saw palmetto (Serenoa repens (Bartr.) Small). Embryos, isolated from immature fruit of native-grown plants, were cultured on Murashige and Skoog medium plus 0.15% (w\\/v) activated charcoal and supplemented with 452 µM 2,4-dichlorophenoxyacetic acid (2,4-D) and 14.7 µM N6-(2-isopentenyl)adenine (2iP). Clusters of somatic embryos developed from all immature zygotic

M. Gallo-Meagher; J. Green

2002-01-01

155

Clonal propagation of Trifolium Pratense, T. Resupinatum and T. Subterraneum by direct somatic embryogenesis on cultured immature embryos  

Microsoft Academic Search

Direct somatic embryogenesis on immature zygotic embryos in vitro has been confirmed for Trifolium pratense and extended to T. resupinatum and T. subterraneum. For all species direct embryo cloning can be achieved on an appropriate basal medium supplemented with 1gl-1 yeast extract and 0.05 mgl-1 BAP. Basal medium\\/sucrose formulation, level of yeast extract and level of BAP affected the nature

G. Maheswaran; E. G. Williams

1986-01-01

156

Bioreactor studies of the effect of medium pH on carrot (Daucus carota L.) somatic embryogenesis  

Microsoft Academic Search

Daucus carota cell differentiation was examined under different medium pH conditions in a controlled bioreactor. Somatic embryogenesis was affected by pH changes. Embryo production was greatest when the pH of the hormone-free medium was maintained at 4.3. However, the same level was not favourable to development since most embryos did not progress to the torpedo and plantlet stages. In contrast,

Véronique Jay; Simone Genestier; Jean-Claude Courduroux

1994-01-01

157

Initiation of somatic embryogenesis in white spruce ( Picea glauca ): genetic control, culture treatment effects, and implications for tree breeding  

Microsoft Academic Search

The degree of genetic control and the effects of cultural treatments on somatic embryogenesis (SE) in white spruce were investigated with material derived from six-parent diallel crosses, including reciprocals. Thirty zygotic embryos from both immature and mature cones of each family were cultured in media with either 2,4-D or Picloram immediately after the collection of cones and after 2 months

Y. S. Park; S. E. Pond; J. M. Bonga

1993-01-01

158

High-efficiency transformation of Lycium barbarum mediated by Agrobacterium tumefaciens and transgenic plant regeneration via somatic embryogenesis  

Microsoft Academic Search

We have developed a reliable and high-frequency system of transformation and regeneration via somatic embryogenesis (SE) of Lycium barbarum. Leaf segments were co-cultivated with Agrobacterium tumefaciens EHA101 (pIG121Hm) carrying the neomycin phosphotransferase II gene as a selectable marker and an intron-#-glucuronidase (GUS) gene as a reporter marker. On the medium for callus-induction, which contained 50 mg l-1 kanamycin (Km), approximately

Z. Hu; J. Yang; G. Guo; G. Zheng

2002-01-01

159

Pretreatments, conditioned medium and co-culture increase the incidence of somatic embryogenesis of different Cichorium species  

PubMed Central

Somatic embryogenesis (SE) in Cichorium involves dedifferentiation and redifferentiation of single cells and can be induced by specific in vitro culture conditions. We have tested the effect of various treatments on the incidence of SE (ISE) of an interspecific embryogenic hybrid (C. endivia x C. intybus) and of different commercial chicories (C. endivia and C. intybus) that are typically recalcitrant to SE in standard culture conditions. We found that the ISE of the hybrid is significantly increased by pretreatment of tissues by submersion in solutions of glycerol, abscisic acid, spermine, putrescine or of combinations of these compounds. Interestingly, the most efficient of these pretreatments also had an unexpectedly high effect on the ISE of the C. intybus cultivars. The ISE of the hybrid and of the commercial chicories were increased when explants were co-cultured with highly embryogenic chicory explants or when they were cultured in conditioned medium. These observations established that unidentified SE-promoting factors are released in the culture medium. HPLC analyses of secreted Arabino-Galactan Proteins (AGPs), which are known to stimulate SE, did not allow identifying a fraction containing differentially abundant AGP candidates. However, pointing to their role in promoting SE, we found that the hybrid had a drastically higher ISE when amino sugars and L-Proline, the putative precursors of secreted AGPs, were both added to the medium. PMID:22301978

Couillerot, Jean-Paul; Windels, David; Vazquez, Franck; Michalski, Jean-Claude; Hilbert, Jean-Louis; Blervacq, Anne-Sophie

2012-01-01

160

Glutathione-S-Transferase is Detected During Somatic Embryogenesis in Chicory  

PubMed Central

Glutathione S-tranferases (GSTs) are a heterogeneous family of proteins, which perform diverse pivotal catalytic and non-enzymatic functions during plant development and in plant stress responses. Previous studies have shown that a GST activity (EC 2.5.1.18) is closely linked with the precocious phases of somatic embryogenesis in leaf tissues of an interspecific chicory hybrid (Cichorium intybus L. var. sativa × C. endivia L. var. latifolia). In order to learn more about the involvement of this enzyme in this process, in situ-hybridization as well as immunolocalization were performed in parallel. GST-mRNAs and proteins were colocalized in small veins, particularly in young protoxylem cell walls. During cell reactivation, the in situ and protein signals became less intense and were associated with chloroplasts. The GST-mRNAs and corresponding proteins were not always colocalized in the same tissues. While high amounts of transcripts could be detected in multicellular embryos, the proteins were not well labeled. Our results indicated that GSTs belong to a complex anti-oxidant mechanism within the cell, and also at the cell wall level. GSTs presence in reactivated cell and multicellular embryos is discussed in relation to redox cell status. PMID:19516999

Galland, Rachel; Blervacq, Anne-Sophie; Blassiau, Christelle; Smagghe, Benoît; Decottignies, Jean-Pierre

2007-01-01

161

A chimeric arabinogalactan protein promotes somatic embryogenesis in cotton cell culture.  

PubMed

Arabinogalactan proteins (AGPs) are a family of extracellular plant proteoglycans implicated in many aspects of plant growth and development, including in vitro somatic embryogenesis (SE). We found that specific AGPs were produced by cotton (Gossypium hirsutum) calli undergoing SE and that when these AGPs were isolated and incorporated into tissue culture medium, cotton SE was promoted. When the AGPs were partly or fully deglycosylated, SE-promoting activity was not diminished. Testing of AGPs separated by reverse-phase high-performance liquid chromatography revealed that the SE-promoting activity resided in a hydrophobic fraction. We cloned a full-length complementary DNA (cotton PHYTOCYANIN-LIKE ARABINOGALACTAN-PROTEIN1 [GhPLA1]) that encoded the protein backbone of an AGP in the active fraction. It has a chimeric structure comprising an amino-terminal signal sequence, a phytocyanin-like domain, an AGP-like domain, and a hydrophobic carboxyl-terminal domain. Recombinant production of GhPLA1 in tobacco (Nicotiana tabacum) cells enabled us to purify and analyze a single glycosylated AGP and to demonstrate that this chimeric AGP promotes cotton SE. Furthermore, the nonglycosylated phytocyanin-like domain from GhPLA1, which was bacterially produced, also promoted SE, indicating that the glycosylated AGP domain was unnecessary for in vitro activity. PMID:22858635

Poon, Simon; Heath, Robyn Louise; Clarke, Adrienne Elizabeth

2012-10-01

162

First Report of Plant Regeneration via Somatic Embryogenesis from Shoot Apex-Derived Callus of Hedychium muluense R.M. Smith  

Microsoft Academic Search

The genus Hedychium consists of about 50 species, with increasing popularity as ornamentals and potential as medicinal crop plants, but there are no reports on somatic embryogenic regeneration of any member of this genus. The objective of this investigation was to establish an in vitro regeneration system based on somatic embryogenesis for Hedychium muluense R.M. Smith using shoot apex-derived callus.

Hamidou F. Sakhanokho; Rowena Y. Kelley; Kanniah Rajasekaran

2008-01-01

163

High Frequency Plant Regeneration from Astragalus melilotoides hypocotyl and stem explants via somatic embryogenesis and organogenesis  

Microsoft Academic Search

An efficient and reproducible procedure is established for the plant regeneration from hypocotyl explants and hypocotyl-or stem-derived calli in Astragalus melilotoides. High frequency somatic embryo formation (98.3%) occurred direct on hypocotyls on Murashige and Skoog (MS) medium supplemented with 2.69 µM NAA and 4.44 µM BA within 5 weeks. Three types of calli were induced from the hypocotyl and stem

Sui-Wen Hou; Jing-Fen Jia

2004-01-01

164

Somatic Embryogenesis from Hairy Roots Transformed by Agrobacterium Rhizogenes in Panax Ginseng  

Microsoft Academic Search

An efficient in vitro protocol for somatic embryo- genesis of hairy roots of Panxa ginseng has been established. Hairy roots of Panax ginseng were obtained after root disks were infected with Agrobacterium rhizogenes A4. Callus was induced on MS (Murashige and Skoog 1962) medium containing 2,4-D (2,4-Dichlorophenoxyacetic acid), BA (6-Benzyl-aminopurine), Kin (Kinetin). The highest frequency of callus formation was 99.3%

Wang Jianhua; Zhao Shoujing; Xue Jian; Xu Lixin; Hou Chunxi; Liang Yanlong

2008-01-01

165

Thidiazuron stimulates shoot organogenesis and somatic embryogenesis in white ash (Fraxinus americana L.)  

Microsoft Academic Search

Immature and mature nonstratified seeds of white ash (Fraxinus americana L.) were dissected transversely and 2\\/3 of each seed was placed onto agar-solidified Murashige and Skoog medium. Adventitious buds, shoots, and somatic embryos formed on callus, cotyledons, and hypocotyls of the resulting seedlings. Shoot organogenesis was induced on explants cultured on medium with 10 µM thidiazuron but not on explants

Sharon Bates; John E. Preece; Nadia E. Navarrete; J. W. Sambeek; Gerald R. Gaffney

1992-01-01

166

Callus production, somatic embryogenesis and plant regeneration of Lycium barbarum root explants  

Microsoft Academic Search

A new micropropagation system for Lycium barbarum (L.) was developed using root explants as starting material. Callus can be produced from root explants on Murashige and Skoog\\u000a (MS) medium containing 0.2 mg dm?3 2,4-dichlorophenoxyacetic acid. After three subcultures on the same medium, callus was then transferred onto the MS medium\\u000a supplemented with 500 mg dm?3 lactalbumin hydrolysate to induce somatic

Z. Hu; Y. Hu; H. H. Gao; X. Q. Guan; D. H. Zhuang

2008-01-01

167

Rapid propagation of lemongrass ( Cymbopogon flexuosus (Nees) Wats.) through somatic embryogenesis in vitro  

Microsoft Academic Search

Somatic embryos induced from callus cultures of lemongrass [Cymbopogon flexuosus (Nees) Wats.] on Murashige and Skoog medium supplemented with 5 mg\\/l of 2,4-D, 0.1 mg\\/l of NAA and 0.5 mg\\/l of Kn developed into plantlets when plated on a medium supplemented with 3 mg\\/l of BA, 1 mg\\/l of GA3 and 0.1 mg\\/l of NAA. The regeneration potential of callus

S. Nayak; B. K. Debata; S. Sahoo

1996-01-01

168

Involvement of peroxidase activity in developing somatic embryos of Medicago arborea L. Identification of an isozyme peroxidase as biochemical marker of somatic embryogenesis.  

PubMed

The legume Medicago arborea L. is very interesting as regards the regeneration of marginal arid soils. The problem is that it does not have a good germinative yield. It was therefore decided to regenerate via somatic embryogenesis and find a marker of embryogenic potential. In this study, peroxidase activity was evaluated in non-embryogenic and embryogenic calli from M. arborea L. A decrease in soluble peroxidase activity is observed in its embryonic calli at the time at which the somatic embryos begin to appear. This activity is always lower in embryonic calli than in non-embryonic ones (unlike what happens in the case of wall-bound peroxidases). These results suggest that peroxidases can be considered to be enzymes involved in somatic embryogenesis in M. arborea. In addition, isozyme analyses were carried out on protein extracts using polyacrylamide gel electrophoresis. The band called P5 was detected only in embryogenic cultures at very early stages of development. This band was digested with trypsin and analyzed using linear ion trap (LTQ) mass spectrometer. In P5 isoform a peroxidase-L-ascorbate peroxidase was identified. It can be used as a marker that allows the identification of embryological potential. PMID:24331422

Gallego, Piedad; Martin, Luisa; Blazquez, Antonio; Guerra, Hilario; Villalobos, Nieves

2014-01-15

169

Pollen embryogenesis to induce, detect, and analyze mutants  

SciTech Connect

The development of fully differentiated plants from individual pollen grains through a series of developmental phases that resemble embryogenesis beginning with the zygote was demonstrated during the mid-1960's. This technology opened the door to the use of haploid plants (sporophytes with the gametic number of chromosomes) for plant breeding and genetic studies, biochemical and metabolic studies, and the selection of mutations. Although pollen embryogenesis has been demonstrated successfully in numerous plant genera, the procedure cannot as yet be used routinely to generate large populations of plants for experiments. Practical results from use of the technology in genetic toxicology research to detect mutations have failed to fully realize the theoretical potential; further developments of the technology could overcome the limitations. Pollen embryogenesis could be used to develop plants from mutant pollen grains to verify that genetic changes are involved. Through either spontaneous or induced chromosome doubling, these plants can be made homozygous and used to analyze genetically the mutants involved. The success of this approach will depend on the mutant frequency relative to the fraction of pollen grains that undergo embryogenesis; these two factors will dictate population size needed for success. Research effort is needed to further develop pollen embryogenesis for use in the detection of genotoxins under both laboratory and in situ conditions.

Constantin, M.J.

1981-01-01

170

Plant regeneration via somatic embryogenesis in Styrian pumpkin: cytological and biochemical investigations  

Microsoft Academic Search

Somatic embryo formation was induced from cotyledon explants of Styrian pumpkin (Cucurbita pepo L. subsp. pepo var. styriaca Greb.) by using a solid MS medium supplemented with 16.11?µM NAA and 4.44?µM BA or 26.85?µM NAA and 13.32?µM BA. The callus proliferation was more efficient on medium supplemented with 26.85?µM NAA and 13.32?µM BA. In contrast, the embryogenic response was higher

A. Urbanek; B. Zechmann; M. Müller

2005-01-01

171

Quantitation of gibberellins and the metabolism of [ 3 H]gibberellin A 1 during somatic embryogenesis in carrot and anise cell cultures  

Microsoft Academic Search

In a carrot (Daucus carota L.) cell line lacking the ability to undergo somatic embryogenasis, and in carrot and anise (Pimpinella anisum L.) cell lines in which embryogenesis could be regulated by presence or absence of 2,4-dichlorophen-oxyacetic acid (2,4-D), in the medium (+2,4-D=no embryogenesis,-2,4-D=embryo differentiation and development), the levels of endogenous gibberellin(s) (GA) were determined by the dwarfrice bioassay, and

Masana Noma; Jochen Huber; Dieter Ernst; Richard P. Pharis

1982-01-01

172

Initiation and maintenance of long term somatic embryogenesis from anthers and ovaries of Vitis longii ‘Microsperma’  

Microsoft Academic Search

Anthers and ovaries of Vitis longii ‘Microsperma’ produced embryogenic callus when cultured on solidified Murashige and Skoog medium with 5µM 2,4-dichlorophenoxyacetic acid (2,4-D) and 1µM benzyladenine (BA). The initial callus was short-lived. However, long-term embryogenesis from callus was maintained through serial transfers by careful selection of clustered embryos with subtending callus. Alternatively, long term culture maintenance was through secondary embryogenesis

D. J. Gray; J. A. Mortensen

1987-01-01

173

Developmental localization and the role of hydroxyproline rich glycoproteins during somatic embryogenesis of banana (Musa spp. AAA)  

PubMed Central

Background Hydroxyproline rich glycoproteins (HRGPs) are implicated to have a role in many aspects of plant growth and development but there is limited knowledge about their localization and function during somatic embryogenesis of higher plants. In this study, the localization and function of hydroxyproline rich glycoproteins in embryogenic cells (ECs) and somatic embryos of banana were investigated by using immunobloting and immunocytochemistry with monoclonal JIM11 and JIM20 antibodies as well as by treatment with 3,4-dehydro-L-proline (3,4-DHP, an inhibitor of extensin biosynthesis), and by immunomodulation with the JIM11 antibody. Results Immunofluorescence labelling of JIM11 and JIM20 hydroxyproline rich glycoprotein epitopes was relatively weak in non-embryogenic cells (NECs), mainly on the edge of small cell aggregates. On the other hand, hydroxyproline rich glycoprotein epitopes were found to be enriched in early embryogenic cells as well as in various developmental stages of somatic embryos. Embryogenic cells (ECs), proembryos and globular embryos showed strong labelling of hydroxyproline rich glycoprotein epitopes, especially in their cell walls and outer surface layer, so-called extracellular matrix (ECM). This hydroxyproline rich glycoprotein signal at embryo surfaces decreased and/or fully disappeared during later developmental stages (e.g. pear-shaped and cotyledonary stages) of embryos. In these later developmental embryogenic stages, however, new prominent hydroxyproline rich glycoprotein labelling appeared in tri-cellular junctions among parenchymatic cells inside these embryos. Overall immunofluorescence labelling of late stage embryos with JIM20 antibody was weaker than that of JIM11. Western blot analysis supported the above immunolocalization data. The treatment with 3,4-DHP inhibited the development of embryogenic cells and decreased the rate of embryo germination. Embryo-like structures, which developed after 3,4-DHP treatment showed aberrant non-compact epidermis with discontinuous ECM at the outer surface as well as much less immunolabelling with the JIM11 antibody. This treatment also decreased the plant regeneration capacity in embryogenic banana cultures. Finally, immunomodulation of surface hydroxyproline rich glycoproteins by co-culture of embryos with the JIM11 antibody resulted in a much lower germination capacity of these embryos. Conclusions These results suggest that hydroxyproline rich glycoproteins play an important developmental role, especially in the process of regeneration and germination of embryos during plant regeneration via somatic embryogenesis. Proper content and localization of hydroxyproline rich glycoproteins seem to be essential for the formation and regeneration of banana somatic embryos. PMID:21349190

2011-01-01

174

Influence of a loblolly pine ( Pinus taeda L.). Culture medium and its components on growth and somatic embryogenesis of the wild carrot ( Daucus carota L.)  

Microsoft Academic Search

A new culture medium, originally designed and shown to grow cell suspensions from a variety of loblolly pine (Pinus taeda L.) explants, was used to study growth and somatic embryogenesis of the wild carrot (Daucus carota L.) in cell suspensions. The new loblolly pine medium (LM) differed from the standard wild carrot medium (WCM) in having very low Ca2+, very

John D. Litvay; Devi C. Verma; Morris A. Johnson

1985-01-01

175

Improved efficiency and normalization of somatic embryogenesis in Triticum aestivum (wheat)  

Microsoft Academic Search

Summary Tissue cultures derived from the scutellum of immature embryos ofTriticum aestivum L. (wheat) gave rise to somatic embryos with a well-defined scutellum and coleoptile as well as one or more shoot primordia and a root primordium. The normal somatic embryos were formed from compact, white callus tissue which was not observed until 4 or more weeks after culture initiation.

Peggy Ozias-Akins; Indra K. Vasil

1983-01-01

176

Developmental patterns during direct somatic embryogenesis in protoplast cultures of european larch ( Larix decidua Mill.)  

Microsoft Academic Search

Protoplasts isolated from embryogenic suspension cultures of European larch (Larix decidua Mill.) were cultured in thin alginate layers using a nylon mesh to enable a monitoring of the development of single cells. The patterns of cell division and differentiation are characterized and compared with zygotic embryogenesis to which homologies can only be drawn to some extent when the protoplasts grow

Jonas Korlach; Kurt Zoglauer

1995-01-01

177

Imaging of polarity during zygotic and somatic embryogenesis of carrot (Daucus carota L.)  

Microsoft Academic Search

In this thesis a study of the regulation of coordinated growth and the development of polarity during embryogenesis of carrot, Daucus carota L., is described. To this end, several microscopical techniques were used, such as light microscopy, fluorescence microscopy, confocal scanning laser microscopy and electron microscopy. Next to this, immunocytochemical methods were used frequently to localize proteins in plant tissue

A. C. J. Timmers

1993-01-01

178

Characterization and expression analysis of SOMATIC EMBRYOGENESIS RECEPTOR KINASE (SERK) genes in sexual and apomictic Paspalum notatum.  

PubMed

The SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) gene plays a fundamental role in somatic embryogenesis of angiosperms, and is associated with apomixis in Poa pratensis. The objective of this work was to isolate, characterize and analyze the expression patterns of SERK genes in apomictic and sexual genotypes of Paspalum notatum. A conserved 200-bp gene fragment was amplified from genomic DNA with heterologous primers, and used to initiate a chromosomal walking strategy for cloning the complete sequence. This procedure allowed the isolation of two members of the P. notatum SERK family; PnSERK1, which is similar to PpSERK1, and PnSERK2, which is similar to ZmSERK2 and AtSERK1. Phylogenetic analyses indicated that PnSERK1 and PnSERK2 represent paralogous sequences. Southern-blot hybridization indicated the presence of at least three copies of SERK genes in the species. qRT-PCR analyses revealed that PnSERK2 was expressed at significantly higher levels than PnSERK1 in roots, leaves, reproductive tissues and embryogenic calli. Moreover, in situ hybridization experiments revealed that PnSERK2 displayed a spatially and chronologically altered expression pattern in reproductive organs of the apomictic genotype with respect to the sexual one. PnSERK2 is expressed in nucellar cells of the apomictic genotype at meiosis, but only in the megaspore mother cell in the sexual genotype. Therefore, apomixis onset in P. notatum seems to be correlated with the expression of PnSERK2 in nucellar tissue. PMID:24146222

Podio, Maricel; Felitti, Silvina Andrea; Siena, Lorena Adelina; Delgado, Luciana; Mancini, Micaela; Seijo, José Guillermo; González, Ana María; Pessino, Silvina Claudia; Ortiz, Juan Pablo A

2014-03-01

179

NORMALIZING SWEET ORANGE (C. SINENSIS (L.) OSBECK) SOMATIC EMBRYOGENESIS WITH SEMIPERMEABLE MEMBRANES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Development of citrus somatic embryos initiated from embryogenic callus generally results in abnormal morphologies during growth and development. Shoots can be regenerated by organogenesis from these abnormal structures, excised and rooted to recover plants. To normalize development, glycerol-indu...

180

High efficiency plant production of North American ginseng via somatic embryogenesis from cotyledon explants  

Microsoft Academic Search

An efficient in vitro protocol for plant production of North American ginseng has been established. The pretreatment of cotyledon\\u000a explants with 1.0 M sucrose at 4°C resulted in an improvement of embryo quality and, combined with a higher sucrose content\\u000a (7%) in induction medium, improved the embryogenesis frequency from 40% to 75% and the number of embryos per explant from\\u000a 10

Sijun Zhou; Daniel C. W. Brown

2006-01-01

181

The Arabidopsis Somatic Embryogenesis Receptor Kinase 1 Gene Is Expressed in Developing Ovules and Embryos and Enhances Embryogenic Competence in Culture1  

PubMed Central

We report here the isolation of the Arabidopsis SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE 1 (AtSERK1) gene and we demonstrate its role during establishment of somatic embryogenesis in culture. The AtSERK1 gene is highly expressed during embryogenic cell formation in culture and during early embryogenesis. The AtSERK1 gene is first expressed in planta during megasporogenesis in the nucleus of developing ovules, in the functional megaspore, and in all cells of the embryo sac up to fertilization. After fertilization, AtSERK1 expression is seen in all cells of the developing embryo until the heart stage. After this stage, AtSERK1 expression is no longer detectable in the embryo or in any part of the developing seed. Low expression is detected in adult vascular tissue. Ectopic expression of the full-length AtSERK1 cDNA under the control of the cauliflower mosaic virus 35S promoter did not result in any altered plant phenotype. However, seedlings that overexpressed the AtSERK1 mRNA exhibited a 3- to 4-fold increase in efficiency for initiation of somatic embryogenesis. Thus, an increased AtSERK1 level is sufficient to confer embryogenic competence in culture. PMID:11706164

Hecht, Valérie; Vielle-Calzada, Jean-Philippe; Hartog, Marijke V.; Schmidt, Ed D.L.; Boutilier, Kim; Grossniklaus, Ueli; de Vries, Sacco C.

2001-01-01

182

GhHmgB3 deficiency deregulates proliferation and differentiation of cells during somatic embryogenesis in cotton.  

PubMed

The proteins of high-mobility group box (HmgB) family were involved in the regulation of transcription and other DNA-dependent processes. To investigate the function of HmgB proteins during cotton somatic embryogenesis (SE), four Gossypium hirsutum HmgB genes were characterized. The gene GhHmgB3 preferentially expressed in embryonic tissues and was studied in detail. RNA interference and over-expression was used to regulate the expression of GhHmgB3 during cotton SE by transforming both hypocotyl and embryogenic calli (ECs) via Agrobacterium tumefaciens. The GhHmgB3-deficient somatic cells of hypocotyls dedifferentiated more vigorously than the control cells, but they failed to differentiate to ECs. In another case, the proliferation and differentiation of GhHmgB3-deficient ECs were significantly improved, but failed to form plantlets. Over-expression of GhHmgB3 had no significant differences in callus initiation and differentiation compared with the control cell lines. The different expression genes between the control and GhHmgB3-deficient ECs were identified by Solexa sequencing technology. The bioinformatics analysis and experimental verification revealed series of abnormal mechanism associated with ?-catenin signalling. These results in response to the down-regulation of GhHmgB3 revealed series of ?-catenin-related mechanisms might be responsible for the deregulation of proliferation and differentiation of cells in cotton SE. PMID:21554528

Hu, Lisong; Yang, Xiyan; Yuan, Daojun; Zeng, Fanchang; Zhang, Xianlong

2011-12-01

183

Developmental Plasticity of Glandular Trichomes into Somatic Embryogenesis in Tilia amurensis  

PubMed Central

Background and Aims In Tilia amurensis, two types of trichomes (hairy and glandular) develop from epidermal surfaces of cotyledons and hypocotyls of zygotic embryos soon after germination. Here, it is demonstrated that glandular trichome initials develop directly into somatic embryos when treated in vitro with 2,4-dichlorophenoxyacetic acid (2,4-D). Methods Zygotic embryos of Tilia amurensis were cultured on Murashige and Skoog medium with 3 % sucrose and various concentrations (0, 2·2, 4·4 and 8·8 µm) of 2,4-D. Morphological development of trichomes and somatic embryos was analysed by scanning electron microscope and light microscope after histological sectioning. Key Results In zygotic embryos cultured on medium with 4·4 µm 2,4-D, formation of hairy trichomes was completely suppressed but formation of glandular trichome initials increased. That some filamentous trichome initials developed directly into somatic embryos was confirmed by histological and scanning electron microscope observation. When explants with different stages of trichome initials (two-, four- and eight-celled filamentous and fully mature trichomes) were temporally pre-treated with 4·4 µm 2,4-D for 24 h and transferred into hormone-free medium, two-celled and four-celled filamentous trichome initials were the effective stage of trichomes for somatic embryo induction. Conclusions It is suggested that early developing filamentous trichome initials have developmental plasticity and that with 2,4-D treatment these trichome initials develop directly into somatic embryos. PMID:17565972

Kim, T. D.; Lee, B. S.; Kim, T. S.; Choi, Y. E.

2007-01-01

184

Direct somatic embryogenesis from pericycle cells of broccoli ( Brassica oleracea L. var. italica) root explants  

Microsoft Academic Search

Cotyledon, hypocotyl or root explants of 7-day-old broccoli seedlings were cultured on Murashige and Skoog (MS) agar or liquid\\u000a medium supplemented with 1.0 mg l?1 2,4-dichlorophenoxyacetic acid (2,4-D). The frequency of direct somatic embryo formation was 100% when root explants were\\u000a cultured in liquid medium. Histological analysis indicated that somatic embryos were initiated directly from the pericycle\\u000a cell layers of root explants

J. L. Yang; E. S. Seong; M. J. Kim; B. K. Ghimire; W. H. Kang; Chang Yeon Yu; Cheng Hao Li

2010-01-01

185

Plant regeneration via somatic embryogenesis from protoplasts of six plant species related to Citrus.  

PubMed

Protoplasts isolated from embryogenic callus of Fortunella polyandra (Ridl.), Atalantia bilocularis (Pieree ex Guill.), Hesperethusa crenulata (Roxb.), Glycosmis pentaphylla (Retz.) Corr., Triphasia trifolia (Burm. f.) P. Wils. and Murraya koenigii (L.) Spreng. were cultured in MT (Murashige and Tucker 1969) basal medium containing 5% sucrose supplemented with 0.0, 0.001, 0.01, 0.1 or 1.0 mg l(-1) BA and 0.6 M sorbitol. The highest plating efficiencies for all species were obtained on MT basal medium containing 5% sucrose supplemented with 0.001 mg l(-1) BA. F. polyandra produced higher percentages of globular somatic embryo development, while A. bilocularis consistently showed a lower percentage of globular somatic embryo development in all 5 concentrations of BA. MT basal medium containing 5% sucrose and supplemented with 0.001 mg l(-1) BA was found to be a suitable medium for development of globular somatic embryos derived from protoplasts to form heart-shaped somatic embryos with cotyledon-like structures. The highest percentages of shoot formation for all 6 species were obtained using 0.1 mg l(-1) GA3. A complete protoplast-to-plant system was developed for F. polyandra, A. bilocularis and T. trifolia, which could facilitate the transfer of nuclear and cytoplasmic genes from these species into cultivated Citrus through protoplast fusion. PMID:24178352

Jumin, H B; Nito, N

1996-01-01

186

Somatic embryogenesis from leaf callus derived from mature trees of the cycad Ceratozamia hildae (Gymnospermae)  

Microsoft Academic Search

A friable and transient embryogenic callus was initiated from pinnae removed from leaves in new vegetative flushes of mature Ceratozamia hildae Landry & Wilson, a cycad. Somatic proembryos developed from the callus approximately 3 months after explanting onto plant growth medium consisting of a modified B5 formulation with 60 g l-1 sucrose, 400 mg l-1 glutamine, 100 mg l-1 arginine,

Richard E. Litz; Pamela A. Moon; Victor M. Chavez

1995-01-01

187

Endogenous Abscisic Acid and Indole-3-Acetic Acid and Somatic Embryogenesis in Cultured Leaf Explants of Pennisetum purpureum Schum. : Effects in Vivo and in Vitro of Glyphosate, Fluridone, and Paclobutrazol.  

PubMed

Effects of application in vivo of glyphosate, fluridone, and paclobutrazol to glasshouse-grown donor plants of Pennisetum purpureum Schum. on endogenous levels of abscisic acid (ABA) and indole-3-acetic acid (IAA) in young leaves and on somatic embryogenesis in cultured leaf explants were studied. Treatment of plants with glyphosate (100 milligrams per liter) resulted in elevated levels of endogenous ABA and IAA in young leaves. In contrast, paclobutrazol (50% active ingredient; 200 milligrams per liter) did not alter the endogenous levels of ABA and IAA. Fluridone (100 milligrams per liter) markedly inhibited synthesis of ABA and leaf explants from fluridone-treated plants lost the capacity for somatic embryogenesis. Explants from glyphosate- or paclobutrazol-treated plants did not show any reduction in embryogenic capacity when compared with untreated control plants. Glyphosate and fluridone were also incorporated into the culture media at various concentrations (0 to 20 milligrams per liter) to study their effects in vitro on somatic embryogenesis in leaf explants from untreated, field-grown plants. Glyphosate was inhibitory to somatic embryogenesis but only at concentrations above 5 milligrams per liter. Fluridone inhibited somatic embryogenesis at all concentrations tested. Inhibition of somatic embryogenesis by fluridone, by either in vivo or in vitro application, could be overcome partially by (+/-)-ABA added to the culture medium. Exogenous application of (+/-)-ABA enhanced somatic embryogenesis and reduced the formation of nonembryogenic callus. Application of IAA or gibberellic acid (GA(3); >5 milligrams per liter) was inhibitory to somatic embryogenesis. These results indicate that endogenous ABA is one of the important factors controlling the embryogenic capacity of leaf explants in Napier grass. PMID:16665403

Rajasekaran, K; Hein, M B; Vasil, I K

1987-05-01

188

An Unusual Abscisic Acid and Gibberellic Acid Synergism Increases Somatic Embryogenesis, Facilitates Its Genetic Analysis and Improves Transformation in Medicago truncatula  

PubMed Central

Somatic embryogenesis (SE) can be readily induced in leaf explants of the Jemalong 2HA genotype of the model legume Medicago truncatula by auxin and cytokinin, but rarely in wild-type Jemalong. Gibberellic acid (GA), a hormone not included in the medium, appears to act in Arabidopsis as a repressor of the embryonic state such that low ABA (abscisic acid): GA ratios will inhibit SE. It was important to evaluate the GA effect in M. truncatula in order to formulate generic SE mechanisms, given the Arabidopsis information. It was surprising to find that low ABA:GA ratios in M. truncatula acted synergistically to stimulate SE. The unusual synergism between GA and ABA in inducing SE has utility in improving SE for regeneration and transformation in M. truncatula. Expression of genes previously shown to be important in M. truncatula SE was not increased. In investigating genes previously studied in GA investigations of Arabidopsis SE, there was increased expression of GA2ox and decreased expression of PICKLE, a negative regulator of SE in Arabidopsis. We suggest that in M. truncatula there are different ABA:GA ratios required for down-regulating the PICKLE gene, a repressor of the embryonic state. In M. truncatula it is a low ABA:GA ratio while in Arabidopsis it is a high ABA:GA ratio. In different species the expression of key genes is probably related to differences in how the hormone networks optimise their expression. PMID:24937316

Nolan, Kim E.; Song, Youhong; Liao, Siyang; Saeed, Nasir A.; Zhang, Xiyi; Rose, Ray J.

2014-01-01

189

Promotive and inhibitory effects of diverse arabinogalactan proteins on Daucus carota L. somatic embryogenesis  

Microsoft Academic Search

.   Secreted arabinogalactan proteins (AGPs), isolated on the basis of specific epitopes, have been reported that can either\\u000a enhance (ZUM18 AGP fraction) or inhibit (ZUM15 AGP fraction) carrot (Daucus carota L.) somatic embryo development (Kreuger and van Holst, 1995, Planta 197: 135–141). Here, we report that addition of the ZUM18\\u000a AGP fraction to different size-fractionated cell populations isolated from embryogenic

Marcel A. J. Toonen; Ed D. L. Schmidt; Ab van Kammen; Sacco C. de Vries

1997-01-01

190

Somatic embryogenesis and plant regeneration from litchi protoplasts isolated from embryogenic suspensions  

Microsoft Academic Search

High yields of protoplasts were isolated from litchi embryogenic suspensions, which were maintained by alternative culture\\u000a in liquid and on solid media containing silver thiosulfate. Protoplasts in liquid culture and agarose beads were unable to\\u000a divide sustainedly, whereas embedding of protoplasts in Ca-alginate supported cell division to microcalli and the direct formation\\u000a of somatic embryos from protoplasts. Nurse cells of

Changhe Yu; Zhenguang Chen; Liuxin Lu; Jinwen Lin

2000-01-01

191

Somatic embryogenesis and plant regeneration in Coronilla varia L. (crownvetch) long-term tissue cultures  

Microsoft Academic Search

Spontaneous recovery of regeneration abilities was observed in a long-term (about two-year-old) crownvetch (Coronilla varia L.) tissue culture permanently grown on MS medium containing 1 mg 1-1 IAA. Somatic embryos and later complete plants differentiated from initially regenerating roots. The formation and development\\u000a of embryos was accompanied by a 10- to 20-fold increase in the content of cardioactive glycosides hyrcanoside

Ji?ina Duškova; Z. Opatrný; Marie Sovová; J. Dušek

1990-01-01

192

Somatic embryogenesis in leaf callus from a mature Quercus suber L. Tree  

Microsoft Academic Search

Summary  Somatic embryos were obtained from a 60-yr-old Quercus suber L. tree. Leaf explants were cultivated on Murashige and Skoog medium with 30 gl?1 sucrose, 3 gl?1 gelrite, pH adjusted to 5.8, and different growth regulator combinations. Callus induction took place at 241C in the dark\\u000a during the first 3 wk. After 3 mo, calluses that showed embryogenic structures were transferred

Glória Pinto; Helena Valentim; Armando Costa; Sílvia Castro; Conceiçăo Santos

2002-01-01

193

Influence of 50 Hz electromagnetic fields on recurrent embryogenesis and germination of cork oak somatic embryos  

Microsoft Academic Search

Plant tissue culture techniques are carried out under environmentally controlled conditions in phytotrons. However, electric\\u000a components of phytotrons generate electromagnetic fields that may act as a environmental factor influencing plant growth and\\u000a morphogenesis. Isolated somatic embryos of Quercus suber, picked from embryogenic lines, were chronically exposed to a 50\\u000a Hz and 15 ?T electromagnetic field generated in a Helmholtz-coil system

Cristina Celestino; Maria Luisa Picazo; Mariano Toribio; Jose Antonio Alvarez-Ude; Jose Luis Bardasano

1998-01-01

194

Somatic embryogenesis from leaf and zygotic embryo explants of Blighia sapida ‘Cheese’ ackee  

Microsoft Academic Search

Summary  This study investigated factors affecting the production of somatic embryos in Blighia sapida (ackee). Explants obtained from fully expanded leaves or cotyledons of immature zygotic embryos excised from brown (BSCZE)\\u000a or green seeds (GSCZE) were cultured on Murashige and Skoog medium supplemented with 9, 18 and 36?M 2,4-dichlorophenoxyacetic acid (2,4-D) and 4.4 or 22.1 ?M benzylaminopurine (BAP) or 0.2–19.9 ?M

S. A. Webster; S. A. Mitchell; W. A. Reid; M. H. Ahmad

2006-01-01

195

Plant regeneration from cultured immature inflorescences of coconut ( Cocos nucifera L.): evidence for somatic embryogenesis  

Microsoft Academic Search

Immature inflorescences of coconut belonging to three different genotypes were cultured on a solid medium supplemented with activated charcoal (2%) and a range of 2,4-dichlorophenoxyacetic acid (2,4-D) concentrations (from 1.5 to 3.5 × 10-4M). Globular white callus formed from immature floral meristems, depending on inflorescence age and 2,4-D concentration. Acquisition of embryogenic competence is described histologically. Somatic embryos presented a

Jean-Luc Verdeil; Christine Huet; Frédérique Grosdemange; Jacqueline Buffard-Morel

1994-01-01

196

Somatic embryogenesis in suspension and suspension-derived callus cultures of Dactylis glomerata  

Microsoft Academic Search

Summary Suspension cultures were initiated from somatic embryos and embryogenic callus ofDactylis glomerata L. in SH-30 liquid medium [Schenk andHildebrandt (1972) containing 30 µM 3,6-dichloro-o-anisic acid (dicamba)] with or without 1.5 gl-1 casein hydrolysate. Established suspension cultures maintained in SH-30 without casein hydrolysate proliferated when cell masses underwent cell division and enlargement. These cultures contained numerous root primordia and increased

D. J. Gray; B. V. Conger; G. E. Hanning

1984-01-01

197

Patterns of expression of the JIM4 arabinogalactan-protein epitope in cell cultures and during somatic embryogenesis in Daucus carota L  

Microsoft Academic Search

Spatiotemporal patterns of expression of the cell-surface arabinogalactan-protein epitope defined by monoclonal antibody JIM4 (J.P. Knox et al., 1989, Development 106, 47–56) have been characterized by indirect immunofluorescence during the process of somatic embryogenesis in Daucus carota L. The JIM 4 epitope (J4e) occurred on cells established in culture from hypocotyl explants which appeared to derive, at least in part,

Nicola J. Stacey; Keith Roberts; J. Paul Knox

1990-01-01

198

Do stress-related phytohormones, abscisic acid and jasmonic acid play a role in the regulation of Medicago sativa L. somatic embryogenesis?  

Microsoft Academic Search

This study examined the role of endogenous abscisic acid (ABA) and jasmonic acid (JA) in indirect somatic embryogenesis of\\u000a Medicago sativa L. A multiplex GC-MS\\/MS technique allowed quantitative single-run analyses of ABA, JA, 12-oxophytodienoic acid (OPDA) and\\u000a indole-3-acetic acid (IAA). The preparation of initial explants led to a strong accumulation of ABA, JA and OPDA but not of\\u000a IAA. Substantially

Izabela Rudu?; Elmar W. Weiler; Ewa K?pczy?ska

2009-01-01

199

Deep Sequencing and Microarray Hybridization Identify Conserved and Species-Specific MicroRNAs during Somatic Embryogenesis in Hybrid Yellow Poplar  

PubMed Central

Background To date, several studies have indicated a major role for microRNAs (miRNAs) in regulating plant development, but miRNA-mediated regulation of the developing somatic embryo is poorly understood, especially during early stages of somatic embryogenesis in hardwood plants. In this study, Solexa sequencing and miRNA microfluidic chips were used to discover conserved and species-specific miRNAs during somatic embryogenesis of hybrid yellow poplar (Liriodendron tulipifera×L. chinense). Methodology/Principal Findings A total of 17,214,153 reads representing 7,421,623 distinct sequences were obtained from a short RNA library generated from small RNAs extracted from all stages of somatic embryos. Through a combination of deep sequencing and bioinformatic analyses, we discovered 83 sequences with perfect matches to known miRNAs from 33 conserved miRNA families and 273 species-specific candidate miRNAs. MicroRNA microarray results demonstrated that many conserved and species-specific miRNAs were expressed in hybrid yellow poplar embryos. In addition, the microarray also detected another 149 potential miRNAs, belonging to 29 conserved families, which were not discovered by deep sequencing analysis. The biological processes and molecular functions of the targets of these miRNAs were predicted by carrying out BLAST search against Arabidopsis thaliana GenBank sequences and then analyzing the results with Gene Ontology. Conclusions Solexa sequencing and microarray hybridization were used to discover 232 candidate conserved miRNAs from 61 miRNA families and 273 candidate species-specific miRNAs in hybrid yellow poplar. In these predicted miRNAs, 64 conserved miRNAs and 177 species-specific miRNAs were detected by both sequencing and microarray hybridization. Our results suggest that miRNAs have wide-ranging characteristics and important roles during all stages of somatic embryogenesis in this economically important species. PMID:22952685

Qiu, Shuai; Zhang, Yanjuan; Wang, Pengkai; Yang, Liwei; Lu, Ye; Shi, Jisen

2012-01-01

200

Somatic embryogenesis and plant regeneration from cultured young inflorescences of Oryza sativa L. (rice)  

Microsoft Academic Search

Compact calli initiated from young inflorescences of Oryza sativa L. (rice) on the Linsmaier and Skoog's (LS) medium containing 1 to 2.5mg\\/l of 2,4-dichlorophen-oxyacetic acid (2,4-D) were\\u000a used for regeneration studies. After smooth and compact nodules appeared, these calli were transferred to the regeneration\\u000a medium containing indole-3-acetic acid (IAA) and either kinetin or 6-benzylaminopurine (BAP). Somatic embryos developed in\\u000a ten

Tsung-Hsien Chen; Ling Lam; Shuh-Chun Chen

1985-01-01

201

A Lower pH Value Benefits Regeneration of Trichosanthes kirilowii by Somatic Embryogenesis, Involving Rhizoid Tubers (RTBs), a Novel Structure  

PubMed Central

A new approach was established for the regeneration of Trichosanthes kirilowii from root, stem, and leaf explants by somatic embryogenesis (SE), involving a previously unreported SE structure, rhizoid tubers (RTBs). During SE, special rhizoids were first induced from root, stem, and leaf explants with average rhizoid numbers of 62.33, 40.17, and 11.53 per explant, respectively, on Murashige and Skoog (MS) medium (pH 4.0) supplemented with 1.0?mg/L 1-naphthaleneacetic acid (NAA) under dark conditions. Further, one RTB was formed from each of the rhizoids on MS medium (pH 4.0) supplemented with 20?mg/L thidiazuron (TDZ) under light conditions. In the suitable range (pH 4.0–9.0), a lower pH value increased the induction of rhizoids and RTBs. Approximately 37.77, 33.47, and 31.07% of in vivo RTBs from root, stem, and leaf explants, respectively, spontaneously developed into multiple plantlets on the same MS medium (supplemented with 20?mg/L TDZ) for induction of RTBs, whereas >95.00% of in vitro RTBs from each kind of explant developed into multiple plantlets on MS medium supplemented with 5.0?mg/L 6-benzylaminopurine (BAP). Morphological and histological analyses revealed that RTB is a novel type of SE structure that develops from the cortex cells of rhizoids. PMID:25744384

Xu, Ke-dong; Chang, Yun-xia; Zhang, Ju; Wang, Pei-long; Wu, Jian-xin; Li, Yan-yan; Wang, Xiao-wen; Wang, Wei; Liu, Kun; Zhang, Yi; Yu, De-shui; Liao, Li-bing; Li, Yi; Ma, Shu-ya; Tan, Guang-xuan; Li, Cheng-wei

2015-01-01

202

The union of somatic gonad precursors and primordial germ cells during C. elegans embryogenesis  

PubMed Central

Somatic gonadal niche cells control the survival, differentiation, and proliferation of germline stem cells. The establishment of this niche-stem cell relationship is critical, and yet the precursors to these two cell types are often born at a distance from one another. The simple C. elegans gonadal primordium, which contains two somatic gonad precursors (SGPs) and two primordial germ cells (PGCs), provides an accessible model for determining how stem cell and niche cell precursors first assemble during development. To visualize the morphogenetic events that lead to formation of the gonadal primordium, we generated transgenic strains to label the cell membranes of the SGPs and PGCs and captured time-lapse movies as the gonadal primordium formed. We identify three distinct phases of SGP behavior: posterior migration along the endoderm towards the PGCs, extension of a single long projection around the adjacent PGC, and a dramatic wrapping over the PGC surfaces. We show that the endoderm and PGCs are dispensable for SGP posterior migration and initiation of projections. However, both tissues are required for the final positioning of the SGPs and the morphology of their projections, and PGCs are absolutely required for SGP wrapping behaviors. Finally, we demonstrate that the basement membrane component laminin, which localizes adjacent to the developing gonadal primordium, is required to prevent the SGPs from over-extending past the PGCs. Our findings provide a foundation for understanding the cellular and molecular regulation of the establishment of a niche-stem cell relationship. PMID:23562590

Rohrschneider, Monica R.; Nance, Jeremy

2013-01-01

203

The union of somatic gonad precursors and primordial germ cells during Caenorhabditis elegans embryogenesis.  

PubMed

Somatic gonadal niche cells control the survival, differentiation, and proliferation of germline stem cells. The establishment of this niche-stem cell relationship is critical, and yet the precursors to these two cell types are often born at a distance from one another. The simple Caenorhabditis elegans gonadal primordium, which contains two somatic gonad precursors (SGPs) and two primordial germ cells (PGCs), provides an accessible model for determining how stem cell and niche cell precursors first assemble during development. To visualize the morphogenetic events that lead to formation of the gonadal primordium, we generated transgenic strains to label the cell membranes of the SGPs and PGCs and captured time-lapse movies as the gonadal primordium formed. We identify three distinct phases of SGP behavior: posterior migration along the endoderm towards the PGCs, extension of a single long projection around the adjacent PGC, and a dramatic wrapping over the PGC surfaces. We show that the endoderm and PGCs are dispensable for SGP posterior migration and initiation of projections. However, both tissues are required for the final positioning of the SGPs and the morphology of their projections, and PGCs are absolutely required for SGP wrapping behaviors. Finally, we demonstrate that the basement membrane component laminin, which localizes adjacent to the developing gonadal primordium, is required to prevent the SGPs from over-extending past the PGCs. Our findings provide a foundation for understanding the cellular and molecular regulation of the establishment of a niche-stem cell relationship. PMID:23562590

Rohrschneider, Monica R; Nance, Jeremy

2013-07-15

204

Hormonally regulated overexpression of Arabidopsis WUS and conifer LEC1 (CHAP3A) in transgenic white spruce: implications for somatic embryo development and somatic seedling growth.  

PubMed

Adult conifers are still recalcitrant in clonal propagation despite significant advances in forest tree biotechnology. Plant regeneration through somatic embryogenesis from explants older than mature zygotic embryos is either difficult or impossible to achieve. To investigate if ectopic expression of transcription factors involved in the induction of the embryogenic process would induce somatic embryogenesis in Picea glauca (white spruce) somatic plants, we used the LEAFY-COTYLEDON1 homolog cloned from Picea mariana, CHAP3A, and Arabidopsis thaliana WUS to transform embryonal mass of P. glauca. Ectopic gene expression was induced by 17-beta-estradiol during stages of somatic embryogenesis (early embryogenesis and late embryogenesis) and somatic seedling growth in the transgenics. Of the two transcription factors, only WUS produced severe phenotypes by disrupting the development of somatic embryos on the maturation medium and inhibiting germination. However, none of the transgenes induced ectopic somatic embryogenesis even in the presence of plant growth regulators. Absolute quantitative PCR confirmed the expression of both CHAP3A and WUS in transgenic embryonal mass and in all parts of somatic seedlings. A high expression of the transgenes did not influence expression profiles of any of the ten other transcription factors tested, some of which have been known to be involved in the process of embryogenesis. Implications of these results for further work are discussed. PMID:20424847

Klimaszewska, Krystyna; Pelletier, Gervais; Overton, Catherine; Stewart, Don; Rutledge, Robert G

2010-07-01

205

Advances in Reprogramming Somatic Cells to Induced Pluripotent Stem Cells  

Microsoft Academic Search

Traditionally, nuclear reprogramming of cells has been performed by transferring somatic cell nuclei into oocytes, by combining\\u000a somatic and pluripotent cells together through cell fusion and through genetic integration of factors through somatic cell\\u000a chromatin. All of these techniques changes gene expression which further leads to a change in cell fate. Here we discuss recent\\u000a advances in generating induced pluripotent

Minal Patel; Shuying Yang

2010-01-01

206

Induced Pluripotent Stem Cell Lines Derived from Human Somatic Cells  

Microsoft Academic Search

Somatic cell nuclear transfer allows trans-acting factors present in the mammalian oocyte to reprogram somatic cell nuclei to an undifferentiated state. We show that four factors (OCT4, SOX2, NANOG, and LIN28) are sufficient to reprogram human somatic cells to pluripotent stem cells that exhibit the essential characteristics of embryonic stem (ES) cells. These induced pluripotent human stem cells have normal

Junying Yu; Maxim A. Vodyanik; Kim Smuga-Otto; Jessica Antosiewicz-Bourget; Jennifer L. Frane; Shulan Tian; Jeff Nie; Gudrun A. Jonsdottir; Victor Ruotti; Ron Stewart; Igor I. Slukvin; James A. Thomson

2007-01-01

207

Alterations in the Transcriptome of Soybean in Response to Enhanced Somatic Embryogenesis Promoted by Orthologs of AGAMOUS-Like15 and AGAMOUS-Like181[C][W][OPEN  

PubMed Central

Somatic embryogenesis (SE) is a poorly understood process during which competent cells respond to inducing conditions, allowing the development of somatic embryos. It is important for the regeneration of transgenic plants, including for soybean (Glycine max). We report here that constitutive expression of soybean orthologs of the Arabidopsis (Arabidopsis thaliana) MADS box genes AGAMOUS-Like15 (GmAGL15) and GmAGL18 increased embryogenic competence of explants from these transgenic soybean plants. To understand how GmAGL15 promotes SE, expression studies were performed. Particular genes of interest involved in embryogenesis (ABSCISIC ACID-INSENSITIVE3 and FUSCA3) were found to be directly up-regulated by GmAGL15 by using a combination of quantitative reverse transcription-polymerase chain reaction and chromatin immunoprecipitation. To look more broadly at changes in gene expression in response to GmAGL15, we assessed the transcriptome using the Affymetrix Soybean Genome Array. Interestingly, the gene expression profile of 35Spro:GmAGL15 explants (0 d in culture) was found to resemble nontransgenic tissue that had been induced for SE by being placed on induction medium for 3 d, possibly explaining the more rapid SE development observed on 35Spro:GmAGL15 tissue. In particular, transcripts from genes related to the stress response showed increased transcript accumulation in explants from 35Spro:GmAGL15 tissue. These same genes also showed increased transcript accumulation in response to culturing nontransgenic soybean explants on the medium used to induce SE. Overexpression of GmAGL15 may enhance SE by making the tissue more competent to respond to 2,4-dichlorophenoxyacetic acid induction by differential regulation of genes such as those involved in the stress response, resulting in more rapid and prolific SE. PMID:24481137

Zheng, Qiaolin; Perry, Sharyn E.

2014-01-01

208

Somatic Embryogenesis in Larix  

Microsoft Academic Search

\\u000a The genus Larix has 10 species and many varieties and hybrids. They are native in the cool-temperate and boreal regions of the northern hemisphere\\u000a and in the Himalaya mountains (Gower & Richards, 1990). An outstanding characteristic of Larix is that it is the only conifer genus that is deciduous. In part because of their deciduous habit, many larches can endure

Jan M. Bonga; Krystyna Klimaszewska; Marie-Anne Lelu; Patrick Aderkas

209

Somatic Embryogenesis in Peach Palm Using the Thin Cell Layer Technique: Induction, Morpho-histological Aspects and AFLP Analysis of Somaclonal Variation  

PubMed Central

Background and Aims The thin cell layer (TCL) technique is based on the use of very small explants and has allowed enhanced in vitro morphogenesis in several plant species. The present study evaluated the TCL technique as a procedure for somatic embryo production and plantlet regeneration of peach palm. Methods TCL explants from different positions in the shoot apex and leaf sheath of peach palm were cultivated in MS culture medium supplemented with 0–600 µm Picloram in the presence of activated charcoal. The production of primary calli and embryogenic calli was evaluated in these different conditions. Histological and amplified fragment length polymorphism (AFLP) analyses were conducted to study in vitro morphogenetic responses and genetic stability, respectively, of the regenerated plantlets. Key Results Abundant primary callus induction was observed from TCLs of the shoot meristem in culture media supplemented with 150–600 µm Picloram (83–97 %, respectively). The production of embryogenic calli depends on Picloram concentration and explant position. The best response observed was 43 % embryogenic callus production from shoot meristem TCL on 300 µm Picloram. In maturation conditions, 34 ± 4 somatic embryos per embryogenic callus were obtained, and 45·0 ± 3·4 % of these fully developed somatic embryos were converted, resulting in plantlets ready for acclimatization, of which 80 % survived. Histological studies revealed that the first cellular division events occurred in cells adjacent to vascular tissue, resulting in primary calli, whose growth was ensured by a meristematic zone. A multicellular origin of the resulting somatic embryos arising from the meristematic zone is suggested. During maturation, histological analyses revealed bipolarization of the somatic embryos, as well as the development of new somatic embryos. AFLP analyses revealed that 92 % of the regenerated plantlets were true to type. The use of TCL explants considerably improves the number of calli and somatic embryos produced in comparison with previously described protocols for in vitro regeneration of peach palm. Conclusions The present study suggests that the TCL somatic embryogenesis protocol developed is feasible, although it still requires further optimization for in vitro multiplication of peach palm, especially the use of similar explants obtained from adult palm trees. PMID:17670751

Steinmacher, D. A.; Krohn, N. G.; Dantas, A. C. M.; Stefenon, V. M.; Clement, C. R.; Guerra, M. P.

2007-01-01

210

New Insights into Somatic Embryogenesis: LEAFY COTYLEDON1, BABY BOOM1 and WUSCHEL-RELATED HOMEOBOX4 Are Epigenetically Regulated in Coffea canephora  

PubMed Central

Plant cells have the capacity to generate a new plant without egg fertilization by a process known as somatic embryogenesis (SE), in which differentiated somatic cells can form somatic embryos able to generate a functional plant. Although there have been advances in understanding the genetic basis of SE, the epigenetic mechanism that regulates this process is still unknown. Here, we show that the embryogenic development of Coffea canephora proceeds through a crosstalk between DNA methylation and histone modifications during the earliest embryogenic stages of SE. We found that low levels of DNA methylation, histone H3 lysine 9 dimethylation (H3K9me2) and H3K27me3 change according to embryo development. Moreover, the expression of LEAFY COTYLEDON1 (LEC1) and BABY BOOM1 (BBM1) are only observed after SE induction, whereas WUSCHEL-RELATED HOMEOBOX4 (WOX4) decreases its expression during embryo maturation. Using a pharmacological approach, it was found that 5-Azacytidine strongly inhibits the embryogenic response by decreasing both DNA methylation and gene expression of LEC1 and BBM1. Therefore, in order to know whether these genes were epigenetically regulated, we used Chromatin Immunoprecipitation (ChIP) assays. It was found that WOX4 is regulated by the repressive mark H3K9me2, while LEC1 and BBM1 are epigenetically regulated by H3K27me3. We conclude that epigenetic regulation plays an important role during somatic embryogenic development, and a molecular mechanism for SE is proposed. PMID:23977240

Nic-Can, Geovanny I.; López-Torres, Adolfo; Barredo-Pool, Felipe; Wrobel, Kazimierz; Loyola-Vargas, Víctor M.; Rojas-Herrera, Rafael; De-la-Peńa, Clelia

2013-01-01

211

Genomewide analysis of small RNAs in nonembryogenic and embryogenic tissues of citrus: microRNA- and siRNA-mediated transcript cleavage involved in somatic embryogenesis.  

PubMed

Somatic embryogenesis (SE) is a process of somatic cells becoming dedifferentiated and generating embryos. SE has been widely used in biotechnology as a powerful way of regeneration and a model system for studying plant embryogenesis, but the controlling mechanisms of SE are far from clear. Here, we show the genomewide profiles of miRNAs/siRNAs and their target genes in nonembryogenic and embryogenic tissues of 'Valencia' sweet orange. By high-throughput sequencing (HTS) of small RNAs and RNA degradome tags, we identified 50 known and 45 novel miRNAs, 130 miniature inverted-repeat transposable elements (MITEs) derived, 94 other and 235 phased small interfering RNAs (siRNAs), as well as 203 target genes. The majority of the abundantly expressed miRNAs/siRNAs exhibit lower expression levels in embryogenic callus (EC) or during SE process than in nonembryogenic callus (NEC), which is supposed to derepress the target genes that are involved in development and stress response, thus to activate the biological processes required for cell differentiation. However, the conserved csi-miR156a/b, miR164b and 171c directed suppression of specific transcription factors (TFs) are supposed to inactivate the postembryonic growth thus to maintain normal SE. In this study, miRNA- and siRNA-mediated silencing of target genes was found under sophisticated regulation in citrus SE system; the enhancement effect of specific conserved miRNAs on SE was discussed, providing new clues for future investigation of mechanisms that control SE. PMID:25615015

Wu, Xiao-Meng; Kou, Shu-Jun; Liu, Yuan-Long; Fang, Yan-Ni; Xu, Qiang; Guo, Wen-Wu

2015-04-01

212

Comparative analysis reveals dynamic changes in miRNAs and their targets and expression during somatic embryogenesis in longan (Dimocarpus longan Lour.).  

PubMed

Somatic embryogenesis (SE), which resembles zygotic embryogenesis, is an essential component of the process of plant cell differentiation and embryo development. Although microRNAs (miRNAs) are important regulators of many plant develop- mental processes, their roles in SE have not been thoroughly investigated. In this study, we used deep-sequencing, computational, and qPCR methods to identify, profile, and describe conserved and novel miRNAs involved in longan (Dimocarpus longan) SE. A total of 643 conserved and 29 novel miRNAs (including star strands) from more than 169 miRNA families were identified in longan embryogenic tissue using Solexa sequencing. By combining computational and degradome sequencing approaches, we were able to predict 2063 targets of 272 miRNAs and verify 862 targets of 181 miRNAs. Target annotation revealed that the putative targets were involved in a broad variety of biological processes, including plant metabolism, signal transduction, and stimulus response. Analysis of stage- and tissue-specific expressions of 20 conserved and 4 novel miRNAs indicated their possible roles in longan SE. These miRNAs were dlo-miR156 family members and dlo-miR166c* associated with early embryonic culture developmental stages; dlo-miR26, dlo-miR160a, and families dlo-miR159, dlo-miR390, and dlo-miR398b related to heart-shaped and torpedo- shaped embryo formation; dlo-miR4a, dlo-miR24, dlo-miR167a, dlo-miR168a*, dlo-miR397a, dlo-miR398b.1, dlo-miR398b.2, dlo-miR808 and dlo-miR5077 involved in cotyledonary embryonic development; and dlo-miR17 and dlo-miR2089*-1 that have regulatory roles during longan SE. In addition, dlo-miR167a, dlo-miR808, and dlo-miR5077 may be required for mature embryo formation. This study is the first reported investigation of longan SE involving large-scale cloning, characterization, and expression profiling of miRNAs and their targets. The reported results contribute to our knowledge of somatic embryo miRNAs and provide insights into miRNA biogenesis and expression in plant somatic embryo development. PMID:23593197

Lin, Yuling; Lai, Zhongxiong

2013-01-01

213

Factors affecting maintenance, proliferation, and germination of secondary somatic embryos of Eucalyptus globulus Labill  

Microsoft Academic Search

The described protocol for repetitive somatic embryogenesis (SE) in Eucalyptus globulus produced more somatic embryos than the primary SE protocol. Primary somatic embryos (induced on MS3NAA) were transferred to the same medium, leading to new cycles of somatic embryos, for at least 2 years. The influence of medium\\u000a (MS and B5), plant growth regulators (auxins and cytokinins), and light on secondary

Gloria Pinto; Yill-Sung Park; Sónia Silva; Lucinda Neves; Clara Araújo; Conceiçăo Santos

2008-01-01

214

High frequency shoot organogenesis and somatic embryogenesis in juvenile and adult tissues of seabuckthorn ( Hippophae rhamnoides L.)  

Microsoft Academic Search

Seabuckthorn (Hippophae rhamnoides) is a multipurpose small tree with unique berries of high nutritional and pharmaceutical values. A clonally propagated plant\\u000a originating from a 20-year-old tree of H. r. rhamnoides × mongolica hybrid cultivar Julia and seedling offspring of this cultivar were investigated regarding induction of shoot organogenesis\\u000a in leaf explants and in roots of intact seedlings, and induction of direct somatic

Sridevy Sriskandarajah; Per-Olof Lundquist

2009-01-01

215

Cloning of genes developmentally regulated during plant embryogenesis  

PubMed Central

Genes specifically induced during somatic embryogenesis may play key roles in plant embryo development. An antiserum against an extract of carrot somatic embryos revealed a few rare antigens induced at the onset of embryogenesis. Through differential immunoadsorption techniques, we purified antibodies against the embryo-specific antigens and probed a phage ? gt11 library of cDNA from carrot somatic embryos. This paper describes three distinct cDNA clones that hybridize to embryo-specific RNAs. Monospecific antibodies, purified by affinity to the recombinant phage fusion proteins, confirm that the cloned cDNAs encode unique embryo-specific peptide antigens. One 50-kDa protein correlates with embryogenic ability in cultures of other plant species, including cereals. Images PMID:16593822

Choi, Jung H.; Liu, Liang-shi; Borkird, Chumpol; Sung, Z. R.

1987-01-01

216

Glutathione improves early somatic embryogenesis in Araucaria angustifolia (Bert) O. Kuntze by alteration in nitric oxide emission.  

PubMed

In this work, it was observed a straight relationship between the manipulation of the reduced glutathione (GSH)/glutathione disulfide (GSSG) ratio, nitric oxide emission and quality and number of early somatic embryos in Araucaria angustifolia, a Brazilian endangered native conifer. In low concentrations GSH (0.01 and 0.1mM) is a potential NO scavenger in the culture medium. Furthermore, it can increase the number of early SE formed in cell suspension culture media in a few days. However, the maintenance in this low redox state lead to a loss of early somatic embryos polarization. In gelled culture medium, high levels of GSH (5mM) allows the development of globular embryos presenting a high NO emission on embryo apex, stressing its importance in the differentiation and cell division. Taken together these results indicate that the modification of the embryogenic cultures redox state might be an effective strategy to develop more efficient embryogenic systems in A. angustifolia. PMID:22921001

Vieira, Leila do Nascimento; Santa-Catarina, Claudete; de Freitas Fraga, Hugo Pacheco; Dos Santos, André Luis Wendt; Steinmacher, Douglas André; Schlogl, Paulo Sérgio; Silveira, Vanildo; Steiner, Neusa; Floh, Eny Iochevet Segal; Guerra, Miguel Pedro

2012-10-01

217

Induction, maturation and germination of holm oak ( Quercus ilex L.) somatic embryos  

Microsoft Academic Search

Somatic embryo induction from immature zygotic embryos followed by embryo development and maturation has been achieved in holm oak (Quercus ilex L.). Different types of explant have been assayed for the induction of somatic embryogenesis. Only immature zygotic embryos, collected in August, were successfully induced. Best results were obtained in Gamborg et al. (1968) medium supplemented with 10 µM BAP

P. V. Mauri; J. A. Manzanera

2003-01-01

218

Advances in Reprogramming Somatic Cells to Induced Pluripotent Stem Cells  

PubMed Central

Traditionally, nuclear reprogramming of cells has been performed by transferring somatic cell nuclei into oocytes, by combining somatic and pluripotent cells together through cell fusion and through genetic integration of factors through somatic cell chromatin. All of these techniques changes gene expression which further leads to a change in cell fate. Here we discuss recent advances in generating induced pluripotent stem cells, different reprogramming methods and clinical applications of iPS cells. Viral vectors have been used to transfer transcription factors (Oct4, Sox2, c-myc, Klf4, and nanog) to induce reprogramming of mouse fibroblasts, neural stem cells, neural progenitor cells, keratinocytes, B lymphocytes and meningeal membrane cells towards pluripotency. Human fibroblasts, neural cells, blood and keratinocytes have also been reprogrammed towards pluripotency. In this review we have discussed the use of viral vectors for reprogramming both animal and human stem cells. Currently, many studies are also involved in finding alternatives to using viral vectors carrying transcription factors for reprogramming cells. These include using plasmid transfection, piggyback transposon system and piggyback transposon system combined with a non viral vector system. Applications of these techniques have been discussed in detail including its advantages and disadvantages. Finally, current clinical applications of induced pluripotent stem cells and its limitations have also been reviewed. Thus, this review is a summary of current research advances in reprogramming cells into induced pluripotent stem cells. PMID:20336395

Patel, Minal; Yang, Shuying

2010-01-01

219

Somatic embryogenesis and rhizogenesis of tissue cultures of two genotypes of Papaver somniferum: relationships to alkaloids production.  

PubMed

PAPAVER SOMNIFERUM L. tissue cultures, issued from various explants (cotyledons, hypocotyls, roots) derived from plantlets belonging to two genotypes, were established on LS solid medium containing growth regulators (NAA, Kin) in various combinations. Hypocotyls and roots were found to be interesting explants to obtain cellular development. Many roots developed on calli growing on a medium containing NAA (1 mg/l) + Kin (0.1 mg/l) for the PS genotype while somatic proembryos redifferentiated on calli issued from PS 1639 genotype. The same growth substance combination was the most favourable for the production of morphinan alkaloids and papaverine: up to 10 x 10 (-3)% DW in roots redifferentiated from PS calluses. PMID:17260250

Laurain-Mattar, D; Gillet-Manceau, F; Buchon, L; Nabha, S; Fliniaux, M A; Jacquin-Bubreuil, A

1999-03-01

220

Proteomic and histological analyses of endosperm development in Cyclamen persicum as a basis for optimization of somatic embryogenesis.  

PubMed

The endosperm plays an important role for the development of zygotic embryos, while somatic embryos lack a seed coat and endosperm and often show physiological disorders. This study aims at elucidating the cellular and physiological processes within the endosperm of the ornamental species Cyclamen persicum Mill. Histological analyses were performed from 0 to 11 weeks after pollination (WAP). At 3WAP, a syncytium was clearly visible with a globular zygotic embryo. From 4WAP, cellularization of the endosperm, at 5WAP a small torpedo shaped embryo, and from 7WAP cell expansion was observed. By 11WAP the endosperm appeared fully differentiated. Total soluble proteins were extracted from the endosperm at 4, 5, 7, 9 and 11WAP and resolved using two dimensional isoelectric focussing/sodium dodecyl sulphate-polyacrylamide gel electrophoresis (2D IEF/SDS-PAGE). A shift from high-molecular-mass proteins to low-molecular-mass proteins during endosperm development was observed. A total of 1137proteinspots/gel were detected in the three protein fractions extracted at 7, 9 and 11WAP. Mass spectrometry analysis of the 48 predominant protein spots in endosperm at 7, 9 and 11WAP resulted in the identification of 62 proteins, ten of which were described for the first time in Cyclamen. Additionally, 186 proteins were identified using the C. persicum embryo proteome reference map. Proteins involved in abscisic acid signalling and oxidative stress responsive proteins were found to be important for seed development in Cyclamen. The new insights into endosperm physiology including storage compounds are discussed. PMID:23352402

Mwangi, Jenniffer Wamaitha; Rode, Christina; Colditz, Frank; Haase, Christin; Braun, Hans-Peter; Winkelmann, Traud

2013-03-01

221

Plant regeneration from somatic embryos in black pepper  

Microsoft Academic Search

Embryogenic callus derived from zygotic embryos of black pepper (Piper nigrum Linn.) were induced to form somatic embryos on solid and liquid Schenk and Hildebrandt basal medium. Callus proliferation,\\u000a somatic embryo-genesis and germination of embryos were achieved in about 8 months in static cultures while it took only 8\\u000a weeks in liquid suspension cultures. The highest number of embryos and

Biju Joseph; Dominic Joseph; V. J. Philip

1997-01-01

222

Development and germination of American chestnut somatic embryos  

Microsoft Academic Search

American chestnut (Castanea dentata (Marsh.) Borkh.) plants were regenerated from developing ovules through somatic embryogenesis.\\u000a On an initiation medium containing 18.18 ?M 2,4-dichlorophenoxyacetic acid and 1.11 ?M 6-benzyladenine (BA), 25 out of 1,576\\u000a ovules were induced to form proembryogenic masses (PEMs). These PEMs were cultivated on a development medium for 4 weeks.\\u000a Individual somatic embryos were then grown on a

Zizhuo Xing; William A. Powell; Charles A. Maynard

1999-01-01

223

Somatic Embryogenesis in the Cycadales  

Microsoft Academic Search

\\u000a The cycads (Fig. 1) constitute remnant species of an ancient class of gymnosperms, the cycadophytes, that evolved from the\\u000a free-sporing progymnosperms, which also gave rise to the coniferophytes. According to Gifford & Foster (1989), the cycadophytes\\u000a have included 3 orders of plants, the extinct Cycadeoidales and Pteridospermales (seed ferns), that are known only from the\\u000a fossil record, and the Cycadales,

Richard E. Litz; Victor M. Chavez; Pamela A. Moon

224

UNG shapes the specificity of AID-induced somatic hypermutation.  

PubMed

Secondary diversification of antibodies through somatic hypermutation (SHM) and class switch recombination (CSR) is a critical component of the immune response. Activation-induced deaminase (AID) initiates both processes by deaminating cytosine residues in immunoglobulin genes. The resulting U:G mismatch can be processed by alternative pathways to give rise to a mutation (SHM) or a DNA double-strand break (CSR). Central to this processing is the activity of uracil-N-glycosylase (UNG), an enzyme normally involved in error-free base excision repair. We used next generation sequencing to analyze the contribution of UNG to the resolution of AID-induced lesions. Loss- and gain-of-function experiments showed that UNG activity can promote both error-prone and high fidelity repair of U:G lesions. Unexpectedly, the balance between these alternative outcomes was influenced by the sequence context of the deaminated cytosine, with individual hotspots exhibiting higher susceptibility to UNG-triggered error-free or error-prone resolution. These results reveal UNG as a new molecular layer that shapes the specificity of AID-induced mutations and may provide new insights into the role of AID in cancer development. PMID:22665573

Pérez-Durán, Pablo; Belver, Laura; de Yébenes, Virginia G; Delgado, Pilar; Pisano, David G; Ramiro, Almudena R

2012-07-01

225

Persecution-induced reduction in earning capacity of Holocaust victims: influence of psychiatric and somatic aspects.  

PubMed

The incidence of mental and somatic sequelae is very high in the group of persons damaged by the Holocaust. Based on the sociomedical criteria prevailing in Germany, the assessment of persecution-induced reduction in earning capacity of Holocaust victims (vMdE) is mainly orientated towards direct Holocaust-induced somatic and mental sequelae but must also take into account the interaction of direct Holocaust-induced damage with subsequently acquired physical, mental, and psychosocial factors. The current medical evaluation is focused on the question whether persecution-induced symptoms are exacerbated by endogenous factors like mental or somatic diseases and/or exogenous factors like life events. In that case the grade of vMdE could be increased. Based on the synopsis of 56 Holocaust victims, we ascertained in this study that newly acquired somatic diseases and psychic morbidities contribute to an increase in persecution-induced mental complaints. PMID:21502774

Müller, Helge; Seifert, Frank; Asemann, Rita; Schütz, Patricia; Maler, Juan-Manuel; Sperling, Wolfgang

2011-01-01

226

Enhancement of American chestnut somatic seedling production  

Microsoft Academic Search

Somatic embryogenesis holds promise for mass propagation of American chestnut trees bred or genetically engineered for resistance to chestnut blight. However, low germination frequency of chestnut somatic embryos has limited somatic seedling production for this forest tree. We tested the effects of culture regime (semi-solid versus liquid), cold treatment, AC and somatic embryo morphology (i.e., cotyledon number) on germination and

G. M. Andrade; S. A. Merkle

2005-01-01

227

Spontaneous chromosome doubling results from nuclear fusion during in vitro maize induced microspore embryogenesis  

Microsoft Academic Search

A multidisciplinary study was carried out to analyse the chromosome doubling process during the early stages of in vitro maize microspore embryogenesis. The main stages (microspore derivatives) that were formed in the course of the culture were analysed. Chromosome number was determined from squashed cells, and DNA content was measured by cytometry. In parallel, an ultrastructural analysis of the microspore

P. Testillano; S. Georgiev; H. L. Mogensen; M. J. Coronado; C. Dumas; M. C. Risueno; E. Matthys-Rochon

2004-01-01

228

Characterization of three heat-shock-protein genes and their developmental regulation during somatic embryogenesis in white spruce [ Picea glauca (Moench) Voss  

Microsoft Academic Search

Three cDNAs (PgEMB22, 27 and 29) predicted to encode low-molecular-weight (LMW) heat-shock proteins (HSPs) were cloned and characterized from white spruce [Picea glauca (Moench) Voss] somatic embryo tissues by differentially screening a cotyledonary embryo cDNA library. Clone PgEMB22 is predicted to encode a putative mitochondria-localized LMW HSP, and PgEMB27 and 29 are predicted to encode different cytoplasmic class II LMW

Jin-Zhuo Dong; David I. Dunstan

1996-01-01

229

Aryl organophosphate flame retardants induced cardiotoxicity during zebrafish embryogenesis: By disturbing expression of the transcriptional regulators.  

PubMed

As a result of the ban on some brominated flame retardants (BFRs), the use of organophosphate flame retardants (OPFRs) increases, and they are detected in multi-environment media at higher frequency and concentrations. However, the toxicity data of OPFRs, especially those on developmental toxicology are quite limited, which prevents an accurate evaluation of their environmental and health risk. Because a previous study reported that two aryl-OPFRs induced cardiotoxicity during zebrafish embryogenesis, we designed experiments to compare the heart developmental toxicity of a series of aryl-OPFRs with alkyl-OPFRs and explored possible internal mechanism. First, acute toxicity of 9 frequently used OPFRs were studied with zebrafish embryos (2-96hpf). By comparing the LC50 and EC50 (pericardium edema) data, two aryl-OPFRs, triphenyl phosphate (TPhP) and cresyl diphenyl phosphate (CDP) showed greater heart developmental toxicity than the others. It was also found that the acute toxicity of OPFRs varied mainly depending on their hydrophobicity. Further study on the cardiotoxicty of TPhP and CDP showed that the cardiac looping progress can be impeded by 0.10mg/L TPhP or CDP exposure. Bradycardia and reduction of myocardium were also observed in 0.50 and 1.0mg/L TPhP groups and 0.10, 0.50, and 1.0mg/L CDP groups. 0-48hpf is the vulnerable window of zebrafish cardiogenesis that can be easily affected by TPhP and CDP. RT-qPCR measurement on the expressions of key transcriptional regulators in cardiogenesis showed that BMP4, NKX2-5, and TBX5 were significantly inhibited at the exposure points of 12hpf and 24hpf which may be the internal factors related to the heart developmental toxicity. As zebrafish is a good model organism for human health study, the present results call for a greater attention to the health risk of fetus in pregnant women exposed to such OPFRs. PMID:25661707

Du, Zhongkun; Wang, Guowei; Gao, Shixiang; Wang, Zunyao

2015-04-01

230

DNA methylation dynamics and MET1a-like gene expression changes during stress-induced pollen reprogramming to embryogenesis  

PubMed Central

Stress-induced plant cell reprogramming involves changes in global genome organization, being the epigenetic modifications key factors in the regulation of genome flexibility. DNA methylation, accomplished by DNA methyltransferases, constitutes a prominent epigenetic modification of the chromatin fibre which is locked in a transcriptionally inactive conformation. Changes in DNA methylation accompany the reorganization of the nuclear architecture during plant cell differentiation and proliferation. After a stress treatment, in vitro-cultured microspores are reprogrammed and change their gametophytic developmental pathway towards embryogenesis, the process constituting a useful system of reprogramming in isolated cells for applied and basic research. Gene expression driven by developmental and stress cues often depends on DNA methylation; however, global DNA methylation and genome-wide expression patterns relationship is still poorly understood. In this work, the dynamics of DNA methylation patterns in relation to nuclear architecture and the expression of BnMET1a-like DNA methyltransferase genes have been analysed during pollen development and pollen reprogramming to embryogenesis in Brassica napus L. by a multidisciplinary approach. Results showed an epigenetic reprogramming after microspore embryogenesis induction which involved a decrease of global DNA methylation and its nuclear redistribution with the change of developmental programme and the activation of cell proliferation, while DNA methylation increases with pollen and embryo differentiation in a cell-type-specific manner. Changes in the presence, abundance, and distribution of BnMET1a-like transcripts highly correlated with variations in DNA methylation. Mature zygotic and pollen embryos presented analogous patterns of DNA methylation and MET1a-like expression, providing new evidence of the similarities between both developmental embryogenic programmes. PMID:23175669

Testillano, Pilar S.

2012-01-01

231

Comparison of Somatic Embryogenesis?derived Coffee (Coffea arabica L.) Plantlets Regenerated in vitro or ex vitro: Morphological, Mineral and Water Characteristics  

PubMed Central

Coffea arabica L. plantlets obtained ex vitro after sowing somatic embryos produced in a bioreactor in horticultural substrate were compared with those obtained in vitro from the same embryo population under conventional culturing conditions on semi?solid media. The intensity and quality of aerial and root system development were compared. Shoot emergence was more efficient in vitro but rooting frequencies were low. In contrast, all ex vitro?regenerated embryos rooted. The cotyledon area of mature embryos produced in a bioreactor positively affected plantlet development when regeneration was carried out ex vitro. Embryos with an intermediate cotyledon area (0·86 cm2) had the highest rates of plant conversion ex vitro (63 %), and also resulted in vigorous plantlets. Mortality was higher in nursery conditions, but better plant development was obtained. The quality of plantlets produced under ex vitro conditions was reflected in better growth of the aerial and root systems, and also by similar morphological, mineral and water status characteristics to seedlings. Unlike roots formed on semi?solid media, those produced in soil were branched, fine (30–50 % had a diameter of less than 0·5 mm) and they bore root hairs. Leaves of plantlets regenerated ex vitro had a histological structure similar to that of seedling leaves, and a lower stomatal density (100 vs. 233 mm–2). Moreover, they were more turgid, as indicated by higher pressure potential (?P) (0·91 vs. 0·30 MPa) and relative water content values (97 vs. 93 %). Furthermore, under in vitro conditions, leaves had larger stomata which were abnormally round and raised. Direct sowing of germinated somatic embryos resulted in the rapid production of vigorous plantlets under ex vitro conditions, whilst removing the need for problematical and costly conventional acclimatization procedures. PMID:12125775

BARRY?ETIENNE, D.; BERTRAND, B.; VASQUEZ, N.; ETIENNE, H.

2002-01-01

232

Redox state of low-molecular-weight thiols and disulphides during somatic embryogenesis of salt-treated suspension cultures of Dactylis glomerata L.  

PubMed

The tripeptide antioxidant ?-L-glutamyl-L-cysteinyl-glycine, or glutathione (GSH), serves a central role in ROS scavenging and oxidative signalling. Here, GSH, glutathione disulphide (GSSG), and other low-molecular-weight (LMW) thiols and their corresponding disulphides were studied in embryogenic suspension cultures of Dactylis glomerata L. subjected to moderate (0.085 M NaCl) or severe (0.17 M NaCl) salt stress. Total glutathione (GSH + GSSG) concentrations and redox state were associated with growth and development in control cultures and in moderately salt-stressed cultures and were affected by severe salt stress. The redox state of the cystine (CySS)/2 cysteine (Cys) redox couple was also affected by developmental stage and salt stress. The glutathione half-cell reduction potential (E(GSSG/2 GSH)) increased with the duration of culturing and peaked when somatic embryos were formed, as did the half-cell reduction potential of the CySS/2 Cys redox couple (E(CySS/2 Cys)). The most noticeable relationship between cellular redox state and developmental state was found when all LMW thiols and disulphides present were mathematically combined into a 'thiol-disulphide redox environment' (E(thiol-disulphide)), whereby reducing conditions accompanied proliferation, resulting in the formation of pro-embryogenic masses (PEMs), and oxidizing conditions accompanied differentiation, resulting in the formation of somatic embryos. The comparatively high contribution of E(CySS/2 Cys) to E(thiol-disulphide) in cultures exposed to severe salt stress suggests that Cys and CySS may be important intracellular redox regulators with a potential role in stress signalling. PMID:22348546

Zagorchev, Lyuben; Seal, Charlotte E; Kranner, Ilse; Odjakova, Mariela

2012-05-01

233

Organogenesis, embryogenesis, and synthetic seed production in Arnebia euchroma —A critically endangered medicinal plant of the Himalaya  

Microsoft Academic Search

Summary  This is the first report of simultaneous organogenesis and somatic embryogenesis in Arnebia euchroma, a highly valued, critically endangered medicinal plant of the Himalaya. Root-derived callus showed only rhizogenesis, whereas\\u000a leaf-derived callus showed simutaneous organogenesis and somatic embryogenesis. Organogenesis was optimal (12.2 shoots per\\u000a culture) in 1 ?M indole-3-butyric acid combined with 2.5 ?M 6-benzyladenine and induction of somatic embryogenesis

Sumit Manjkhola; Uppeandra Dhar; Meena Joshi

2005-01-01

234

Excessive Dpp signaling induces cardial apoptosis through dTAK1 and dJNK during late embryogenesis of Drosophila  

PubMed Central

Background To identify genes involved in the heart development of Drosophila, we found that embryos lacking raw function exhibited cardial phenotypes. raw was initially identified as a dorsal open group gene. The dorsal open phenotype was demonstrated to be resulted from the aberrant expression of decapentaplegic (dpp), a member of the tumor growth factor beta (TGF-?), signaling pathway. Despite the role of dpp in pattering cardioblasts during early embryogenesis of Drosophila have been demonstrated, how mutation in raw and/or excessive dpp signaling involves in the differentiating heart of Drosophila has not been fully elaborated at late stages. Results We show that raw mutation produced a mild overspecification of cardial cells at stage 14, but these overproduced cells were mostly eliminated in late mutant embryos due to apoptosis. Aberrant dpp signaling is likely to contribute to the cardial phenotype found in raw mutants, because expression of dpp or constitutively activated thickven (tkvCA), the type I receptor of Dpp, induced a raw-like phenotype. Additionally, we show that dpp induced non-autonomous apoptosis through TGF? activated kinase 1 (TAK1), because mis-expression of a dominant negative form of Drosophila TAK1 (dTAK1DN) was able to suppress cell death in raw mutants or embryos overexpressing dpp. Importantly, we demonstrated that dpp induce its own expression through dTAK1, which also leads to the hyperactivation of Drosophila JNK (DJNK). The hyperactivated DJNK was attributed to be the cause of Dpp/DTAK1-induced apoptosis because overexpression of a dominant negative DJNK, basket (bskDN), suppressed cell death induced by Dpp or DTAK1. Moreover, targeted overexpression of the anti-apoptotic P35 protein, or a dominant negative proapoptotic P53 (P53DN) protein blocked Dpp/DTAK1-induced apoptosis, and rescued heart cells under the raw mutation background. Conclusions We find that ectopic Dpp led to DJNK-dependent cardial apoptosis through the non-canonical TGF-? pathway during late embryogenesis of Drosophila. This certainly will increase our understanding of the pathogenesis of cardiomyopathy, because haemodynamic overload can up-regulate TGF-? and death of cardiomyocytes is observed in virtually every myocardial disease. Thus, our study may provide possible medical intervention for human cardiomyopathy. PMID:22114909

2011-01-01

235

Pine embryogenesis  

PubMed Central

In plants, programmed cell death (PCD) is an important mechanism that controls normal growth and development as well as many defence responses. At present, research on PCD in different plant species is actively carried out due to the possibilities offered by modern methods in molecular biology and the increasing amount of genome data. The pine seed provides a favourable model for PCD because it represents an interesting inheritance of seed tissues as well as an anatomically well-described embryogenesis during which several tissues die via morphologically different PCD processes. PMID:19826239

Sutela, Suvi; Tillman-Sutela, Eila; Kauppi, Anneli; Jokela, Anne; Sarjala, Tytti; Häggman, Hely

2009-01-01

236

Growth regulators influence the fatty acid profiles of in vitro induced jojoba somatic embryos  

Microsoft Academic Search

Inducing somatic embryogensis from jojoba [Simmondsia chinensis (Link) Schneider] explants to produce artificial seeds in the laboratory (in vitro) may prove highly profitable, as the seeds\\u000a contain a characteristic liquid wax of economic importance in industry, nutrition and medicine. Thus, there is a need to examine\\u000a the effect of the factors involved in the in vitro process on the quality

Mohammed A. M. Aly; Essam A. Amer; Wasef A. Al-Zayadneh; Alaa E. Negm Eldin

2008-01-01

237

Hemoglobin Control of Cell Survival/Death Decision Regulates in Vitro Plant Embryogenesis1[W][OPEN  

PubMed Central

Programmed cell death (PCD) in multicellular organisms is a vital process in growth, development, and stress responses that contributes to the formation of tissues and organs. Although numerous studies have defined the molecular participants in apoptotic and PCD cascades, successful identification of early master regulators that target specific cells to live or die is limited. Using Zea mays somatic embryogenesis as a model system, we report that the expressions of two plant hemoglobin (Hb) genes (ZmHb1 and ZmHb2) regulate the cell survival/death decision that influences somatic embryogenesis through their cell-specific localization patterns. Suppression of either of the two ZmHbs is sufficient to induce PCD through a pathway initiated by elevated NO and Zn2+ levels and mediated by production of reactive oxygen species. The effect of the death program on the fate of the developing embryos is dependent on the localization patterns of the two ZmHbs. During somatic embryogenesis, ZmHb2 transcripts are restricted to a few cells anchoring the embryos to the subtending embryogenic tissue, whereas ZmHb1 transcripts extend to several embryonic domains. Suppression of ZmHb2 induces PCD in the anchoring cells, allowing the embryos to develop further, whereas suppression of ZmHb1 results in massive PCD, leading to abortion. We conclude that regulation of the expression of these ZmHbs has the capability to determine the developmental fate of the embryogenic tissue during somatic embryogenesis through their effect on PCD. This unique regulation might have implications for development and differentiation in other species. PMID:24784758

Huang, Shuanglong; Hill, Robert D.; Wally, Owen S.D.; Dionisio, Giuseppe; Ayele, Belay T.; Jami, Sravan Kumar; Stasolla, Claudio

2014-01-01

238

Somatic hybridization in Citrus: navel orange (C. sinensis Osb.) and grapefruit (C. paradisi Macf.).  

PubMed

Protoplasts of navel orange, isolated from embryogenic nucellar cell suspension culture, were fused with protoplasts of grapefruit isolated from leaf tissue. The fusion products were cultured in the hormone-free medium containing 0.6 M sucrose. Under the culture conditions, somatic embryogenesis of navel orange protoplasts was suppressed, while cell division of grapefruit mesophyll protoplasts was not induced. Six embryoids were obtained and three lines regenerated to complete plants through embryogenesis. Two of the regenerated lines exhibited intermediate morphological characteristics of the parents in the leaf shape. Chromosome counts showed that these regenerated plants had expected 36 chromosomes (2n=2x=18 for each parent). The rDNA analysis using biotin-labeled rRNA probes confirmed the presence of genomes from both parents in these plants. This somatic hybridization system would be useful for the practical Citrus breeding. PMID:24225818

Ohgawara, T; Kobayashi, S; Ishii, S; Yoshinaga, K; Oiyama, I

1989-11-01

239

An artificial promoter construct for heat-inducible misexpression during fish embryogenesis  

Microsoft Academic Search

Beside spatial distribution, timing of gene expression is a key parameter controlling gene function during embryonic development. Gain-of-function experiments can therefore have quite opposing results, depending on the time of gene activation. Induction techniques are necessary to control timing in these experiments from outside of the organism. Natural heat shock promoters constitute a simple inducible misexpression system, the main disadvantage

Baubak Bajoghli; Narges Aghaallaei; Thomas Heimbucher; Thomas Czerny

2004-01-01

240

Partial Somatic to Stem Cell Transformations Induced By Cell-Permeable Reprogramming Factors  

PubMed Central

The production of pluripotent stem cells (iPSCs) for therapeutic applications will require practical methods to achieve tight temporal and quantitative control of reprogramming factor (RF) expression, while avoiding the mutagenic potential of gene transfer. Toward this end, we have developed cell-permeable RF proteins (CP-RFs) incorporating newly developed macromolecule transduction domains (MTDs). Treatment of human dermal fibroblasts (HDFs) with combinations of cell-permeable OCT4, SOX2, KLF4, CMYC and either NANOG or LIN28 proteins induced the outgrowth of stem cell-like colonies (iSCs). iSC colonies generated with CP-RFs resembled embryonic stem cells with regard to morphology, biomarker expression, and extended capacity for self-renewal, but failed to expand as iPSC or ES cell lines. Partial reprogramming appears to be a common response to protein-based delivery of programming factors into somatic cells. PMID:24618595

Lim, Junghee; Kim, Junghee; Kang, Jinsun; Jo, Daewoong

2014-01-01

241

Partial somatic to stem cell transformations induced by cell-permeable reprogramming factors.  

PubMed

The production of pluripotent stem cells (iPSCs) for therapeutic applications will require practical methods to achieve tight temporal and quantitative control of reprogramming factor (RF) expression, while avoiding the mutagenic potential of gene transfer. Toward this end, we have developed cell-permeable RF proteins (CP-RFs) incorporating newly developed macromolecule transduction domains (MTDs). Treatment of human dermal fibroblasts (HDFs) with combinations of cell-permeable OCT4, SOX2, KLF4, CMYC and either NANOG or LIN28 proteins induced the outgrowth of stem cell-like colonies (iSCs). iSC colonies generated with CP-RFs resembled embryonic stem cells with regard to morphology, biomarker expression, and extended capacity for self-renewal, but failed to expand as iPSC or ES cell lines. Partial reprogramming appears to be a common response to protein-based delivery of programming factors into somatic cells. PMID:24618595

Lim, Junghee; Kim, Junghee; Kang, Jinsun; Jo, Daewoong

2014-01-01

242

Cell therapy using induced pluripotent stem cells or somatic stem cells: this is the question.  

PubMed

A lot of effort has been developed to bypass the use of embryonic stem cells (ES) in human therapies, because of several concerns and ethical issues. Some unsolved problems of using stem cells for human therapies, excluding the human embryonic origin, are: how to regulate cell plasticity and proliferation, immunological compatibility, potential adverse side-effects when stem cells are systemically administrated, and the in vivo signals to rule out a specific cell fate after transplantation. Currently, it is known that almost all tissues of an adult organism have somatic stem cells (SSC). Whereas ES are primary involved in the genesis of new tissues and organs, SSC are involved in regeneration processes, immuno-regulatory and homeostasis mechanisms. Although the differentiating potential of ES is higher than SSC, several studies suggest that some types of SSC, such as mesenchymal stem cells (MSC), can be induced epigenetically to differentiate into tissue-specific cells of different lineages. This unexpected pluripotency and the variety of sources that they come from, can make MSC-like cells suitable for the treatment of diverse pathologies and injuries. New hopes for cell therapy came from somatic/mature cells and the discovery that could be reprogrammed to a pluripotent stage similar to ES, thus generating induced pluripotent stem cells (iPS). For this, it is necessary to overexpress four main reprogramming factors, Sox2, Oct4, Klf4 and c-Myc. The aim of this review is to analyze the potential and requirements of cellular based tools in human therapy strategies, focusing on the advantage of using MSC over iPS. PMID:22329581

Somoza, Rodrigo A; Rubio, Francisco J

2012-05-01

243

The role of Krüppel-like factors in the reprogramming of somatic cells to induced pluripotent stem cells  

PubMed Central

Summary The potential for clinical application of pluripotent embryonic stem cells is immense but hampered by moral and ethical complications. Recent advances in the reprogramming of somatic cells by defined factors to a state that resemble embryonic stem cells have created tremendous excitement in the field. Four factors, Sox2, Oct4, Klf4 and c-Myc, when exogenously introduced into somatic cells, can lead to the formation of induced pluripotent stem (iPS) cells that have the capacity for self-renewal and differentiation into tissues of all three germ layers. In this review, we focus on the role of Krüppel-like factors (KLFs) in regulating somatic cell reprogramming. KLFs are zinc finger-containing transcription factors with diverse biological functions. We first provide an overview of the KLF family of regulatory proteins, paying special attention to the established biological and biochemical functions of KLF4 and KLF5. We then review the role of KLFs in somatic cell reprogramming and delineate the putative mechanism by which KLFs participates the establishment and self-renewal of iPS cells. Further research is likely to provide additional insight into the mechanisms of somatic cell reprogramming and refinement of the technique with which to generate clinically relevant iPS cells. PMID:19688699

Nandan, Mandayam O.; Yang, Vincent W.

2009-01-01

244

HMGA1 Reprograms Somatic Cells into Pluripotent Stem Cells by Inducing Stem Cell Transcriptional Networks  

PubMed Central

Background Although recent studies have identified genes expressed in human embryonic stem cells (hESCs) that induce pluripotency, the molecular underpinnings of normal stem cell function remain poorly understood. The high mobility group A1 (HMGA1) gene is highly expressed in hESCs and poorly differentiated, stem-like cancers; however, its role in these settings has been unclear. Methods/Principal Findings We show that HMGA1 is highly expressed in fully reprogrammed iPSCs and hESCs, with intermediate levels in ECCs and low levels in fibroblasts. When hESCs are induced to differentiate, HMGA1 decreases and parallels that of other pluripotency factors. Conversely, forced expression of HMGA1 blocks differentiation of hESCs. We also discovered that HMGA1 enhances cellular reprogramming of somatic cells to iPSCs together with the Yamanaka factors (OCT4, SOX2, KLF4, cMYC – OSKM). HMGA1 increases the number and size of iPSC colonies compared to OSKM controls. Surprisingly, there was normal differentiation in vitro and benign teratoma formation in vivo of the HMGA1-derived iPSCs. During the reprogramming process, HMGA1 induces the expression of pluripotency genes, including SOX2, LIN28, and cMYC, while knockdown of HMGA1 in hESCs results in the repression of these genes. Chromatin immunoprecipitation shows that HMGA1 binds to the promoters of these pluripotency genes in vivo. In addition, interfering with HMGA1 function using a short hairpin RNA or a dominant-negative construct blocks cellular reprogramming to a pluripotent state. Conclusions Our findings demonstrate for the first time that HMGA1 enhances cellular reprogramming from a somatic cell to a fully pluripotent stem cell. These findings identify a novel role for HMGA1 as a key regulator of the stem cell state by inducing transcriptional networks that drive pluripotency. Although further studies are needed, these HMGA1 pathways could be exploited in regenerative medicine or as novel therapeutic targets for poorly differentiated, stem-like cancers. PMID:23166588

Shah, Sandeep N.; Kerr, Candace; Cope, Leslie; Zambidis, Elias; Liu, Cyndi; Hillion, Joelle; Belton, Amy; Huso, David L.; Resar, Linda M. S.

2012-01-01

245

Identification of cells deficient in signaling-induced alternative splicing by use of somatic cell genetics.  

PubMed Central

In recent years, a growing number of mammalian genes have been shown to undergo alternative splicing in response to extracellular stimuli. However, the factors and pathways involved in such signal-induced alternative splicing are almost entirely unknown. Here we describe a novel method for identifying candidate trans-acting factors that are involved in regulating mammalian alternative splicing, using the activation-induced alternative splicing of the human CD45 gene in T cells as a model system. We generated a cell line that stably expresses a CD45 minigene-based GFP reporter construct, such that the levels of green-fluorescent protein (GFP) expressed in the cell reflect the splicing state of the endogenous CD45 gene. Following mutagenesis of this cell line, and multiple rounds of selection for cells that displayed aberrant levels of GFP expression, we isolated several cell lines that are at least partially defective in their ability to support regulated alternative splicing of endogenous CD45 pre-mRNA in response to cell stimulation. Thus we have successfully isolated mutants in a mammalian alternative splicing pathway through use of a somatic cell-based genetic screen. This study clearly demonstrates the feasibility of using genetic screens to further our understanding of the regulation of mammalian splicing, particularly as it occurs in response to environmental cues. PMID:12515380

Sheives, Paul; Lynch, Kristen W

2002-01-01

246

Genotoxic damage induced by isopropanol in germinal and somatic cells of Drosophila melanogaster.  

PubMed

Isopropanol (isopropyl alcohol, 2-propanol, IPA) is a volatile solvent widely used in domestic or industrial environments and reported as innocuous in various test systems. The aim of this work was to search for in vivo genotoxic effects of IPA in Drosophila melanogaster, studying its ability to induce nondisjunction (ND) in females, sex linked recessive lethals (SLRL) in males, and somatic mutation and/or recombination (SMART) in larvae. Treatments were acute (60min) and were administered via inhalation. IPA had low toxicity in adult flies (75% IPA mortality index, MI=12.7% (females) and 2.6% (males)) and larvae (MI=14.3%, 75% IPA). Female fertility was severely affected during the first 24h (brood I, BI) after treatment, but, afterwards, control values were recovered. IPA induced a 50-fold increase of ND (%) in 24h old females, and a six-fold rise in 4-5 d old BI offspring. Nondisjunction frequencies (%) in the offspring of broods II to V (24h in each case) were similar to control values. IPA doses of 25% and 50% (v/v), tested in 24h old females, showed a significant dose-dependent increase of ND(%)in BI only, with control values in subsequent broods. Flies gave normal offspring when kept in regular media for 24h before mating. The eye spot test (SMART) showed a significant increase at 50% IPA (p<0.05, m=2), but the response was not dose-dependent. IPA failed to induce SLRL in any of the spermatogenesis stages tested. These findings suggest that the main effect of IPA is to induce chromosomal malsegregation; IPA must be present at the resumption of M-phase I after fertilization, to exert these effects. The alcohol does not affect DNA directly, but perturbations of the nuclear membrane may be responsible for induction of ND. PMID:22001194

Palermo, Ana María; Mudry, Marta Dolores

2011-12-24

247

Concise Review: Generation of Neurons From Somatic Cells of Healthy Individuals and Neurological Patients Through Induced Pluripotency or Direct Conversion  

PubMed Central

Access to healthy or diseased human neural tissue is a daunting task and represents a barrier for advancing our understanding about the cellular, genetic, and molecular mechanisms underlying neurogenesis and neurodegeneration. Reprogramming of somatic cells to pluripotency by transient expression of transcription factors was achieved a few years ago. Induced pluripotent stem cells (iPSC) from both healthy individuals and patients suffering from debilitating, life-threatening neurological diseases have been differentiated into several specific neuronal subtypes. An alternative emerging approach is the direct conversion of somatic cells (i.e., fibroblasts, blood cells, or glial cells) into neuron-like cells. However, to what extent neuronal direct conversion of diseased somatic cells can be achieved remains an open question. Optimization of current expansion and differentiation approaches is highly demanded to increase the differentiation efficiency of specific phenotypes of functional neurons from iPSCs or through somatic cell direct conversion. The realization of the full potential of iPSCs relies on the ability to precisely modify specific genome sequences. Genome editing technologies including zinc finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeat/CAS9 RNA-guided nucleases have progressed very fast over the last years. The combination of genome-editing strategies and patient-specific iPSC biology will offer a unique platform for in vitro generation of diseased and corrected neural derivatives for personalized therapies, disease modeling and drug screening. Stem Cells 2014;32:2811–2817 PMID:24989459

Velasco, Iván; Salazar, Patricia; Giorgetti, Alessandra; Ramos-Mejía, Verónica; Castańo, Julio; Romero-Moya, Damiŕ; Menendez, Pablo

2014-01-01

248

Concise review: Generation of neurons from somatic cells of healthy individuals and neurological patients through induced pluripotency or direct conversion.  

PubMed

Access to healthy or diseased human neural tissue is a daunting task and represents a barrier for advancing our understanding about the cellular, genetic, and molecular mechanisms underlying neurogenesis and neurodegeneration. Reprogramming of somatic cells to pluripotency by transient expression of transcription factors was achieved a few years ago. Induced pluripotent stem cells (iPSC) from both healthy individuals and patients suffering from debilitating, life-threatening neurological diseases have been differentiated into several specific neuronal subtypes. An alternative emerging approach is the direct conversion of somatic cells (i.e., fibroblasts, blood cells, or glial cells) into neuron-like cells. However, to what extent neuronal direct conversion of diseased somatic cells can be achieved remains an open question. Optimization of current expansion and differentiation approaches is highly demanded to increase the differentiation efficiency of specific phenotypes of functional neurons from iPSCs or through somatic cell direct conversion. The realization of the full potential of iPSCs relies on the ability to precisely modify specific genome sequences. Genome editing technologies including zinc finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeat/CAS9 RNA-guided nucleases have progressed very fast over the last years. The combination of genome-editing strategies and patient-specific iPSC biology will offer a unique platform for in vitro generation of diseased and corrected neural derivatives for personalized therapies, disease modeling and drug screening. PMID:24989459

Velasco, Iván; Salazar, Patricia; Giorgetti, Alessandra; Ramos-Mejía, Verónica; Castańo, Julio; Romero-Moya, Damiŕ; Menendez, Pablo

2014-11-01

249

Comparative proteomic analysis of somatic embryo maturation in Carica papaya L.  

PubMed Central

Background Somatic embryogenesis is a complex process regulated by numerous factors. The identification of proteins that are differentially expressed during plant development could result in the development of molecular markers of plant metabolism and provide information contributing to the monitoring and understanding of different biological responses. In addition, the identification of molecular markers could lead to the optimization of protocols allowing the use of biotechnology for papaya propagation and reproduction. This work aimed to investigate the effects of polyethylene glycol (PEG) on somatic embryo development and the protein expression profile during somatic embryo maturation in papaya (Carica papaya L.). Results The maturation treatment supplemented with 6% PEG (PEG6) resulted in the greatest number of somatic embryos and induced differential protein expression compared with cultures grown under the control treatment. Among 135 spots selected for MS/MS analysis, 76 spots were successfully identified, 38 of which were common to both treatments, while 14 spots were unique to the control treatment, and 24 spots were unique to the PEG6 treatment. The identified proteins were assigned to seven categories or were unclassified. The most representative class of proteins observed in the control treatment was associated with the stress response (25.8%), while those under PEG6 treatment were carbohydrate and energy metabolism (18.4%) and the stress response (18.4%). Conclusions The differential expression of three proteins (enolase, esterase and ADH3) induced by PEG6 treatment could play an important role in maturation, and these proteins could be characterized as candidate biomarkers of somatic embryogenesis in papaya. PMID:25076862

2014-01-01

250

Somatic cells, stem cells, and induced pluripotent stem cells: how do they now contribute to conservation?  

PubMed

More than a decade has now passed since the birth of the first endangered species produced from an adult somatic cell reprogrammed by somatic cell nuclear transfer. At that time, advances made in domestic and laboratory animal species provided the necessary foundation for attempting cutting-edge technologies on threatened and endangered species. In addition to nuclear transfer, spermatogonial stem cell transplantation and induction of pluripotent stem cells have also been explored. Although many basic scientific questions have been answered and more than 30 wild species have been investigated, very few successes have been reported. The majority of studies document numerous obstacles that still need to be overcome to produce viable gametes or embryos for healthy offspring production. This chapter provides an overview of somatic cell and stem cell technologies in different taxa (mammals, fishes, birds, reptiles and amphibians) and evaluates the potential and impact of these approaches for animal species conservation. PMID:25091918

Mastromonaco, Gabriela F; González-Grajales, L Antonio; Filice, Melissa; Comizzoli, Pierre

2014-01-01

251

Cold Acclimation-Induced WAP27 Localized in Endoplasmic Reticulum in Cortical Parenchyma Cells of Mulberry Tree Was Homologous to Group 3 Late-Embryogenesis Abundant Proteins1  

PubMed Central

We have shown that two 27-kD proteins, designated as WAP27A and WAP27B, were abundantly accumulated in endoplasmic reticulum-enriched fractions isolated from cortical parenchyma cells of mulberry tree (Morus bombycis Koidz.) during winter (N. Ukaji, C. Kuwabara, D. Takezawa, K. Arakawa, S. Yoshida, S. Fujikawa [1999] Plant Physiol 120: 480–489). In the present study, cDNA clones encoding WAP27A and WAP27B were isolated and characterized. The deduced amino acid sequences of WAP27A and WAP27B cDNAs had 12 repeats of an 11-mer amino acid motif that was the common feature of group 3 late-embryogenesis-abundant proteins. Under field conditions, transcripts of WAP27 genes were initially detected in mid-October, reached maximum level from mid-November to mid-December, and then gradually decreased. The transcript levels of WAP27 genes in cortical parenchyma cells harvested in October was drastically induced by cold treatment within a few days, whereas those in cortical parenchyma cells harvested in August were low even by cold treatment for 3 weeks. Immunocytochemical analysis by electron microscopy confirmed that WAP27 was localized specifically in vesicular-form ER and also localized in dehydration-induced multiplex lamellae-form ER. The role of WAP27 in the ER is discussed in relation to acquisition of freezing tolerance of cortical parenchyma cells in mulberry tree during winter. PMID:11500557

Ukaji, Norifumi; Kuwabara, Chikako; Takezawa, Daisuke; Arakawa, Keita; Fujikawa, Seizo

2001-01-01

252

Enhanced adventive embryogenesis resulting from plasmolysis of cultured wild carrot cells  

Microsoft Academic Search

Adventive embryogenesis in vitro-grown somatic cells of Daucus carota L. was increased three-fold by a 45 min plasmolysis pre-treatment using 1M sucrose solutions. A high degree of synchronous development also resulted from this treatment. The enhancement of embryogenesis is interpreted as an increase in the regeneration of cells which have become physiologically somewhat isolated from the tissue of their origin

D. F. Wetherell

1984-01-01

253

Generation of mouse and human induced pluripotent stem cells (iPSC) from primary somatic cells.  

PubMed

Cellular reprogramming consists of the conversion of differentiated cells into pluripotent cells; the so-called induced Pluripotent Stem Cells. iPSC are amenable to in vitro manipulation and, in theory, direct production of any differentiated cell type. Furthermore, iPSC can be obtained from sick individuals and subsequently used for disease modeling, drug discovery and regenerative treatments. iPSC production was first achieved by transducing, with the use of retroviral vectors, four specific transcription factors: Oct4, Klf4, Sox2 and c-Myc (OKSM), into primary cells in culture Takahashi and Yamanaka, (Cell 126(4):663-676, 2006). Many alternative protocols have since been proposed: repeated transfections of expression plasmids containing the four pluripotency-associated genes Okita et al. (Science 322(5903):949-953, 2008), lentiviral delivery of the four factors Sommer et al. (Stem Cells 27(3):543-549, 2009), Sendai virus delivery Fusaki et al. (Proceedings of the Japan Academy. Series B, Physical and Biological Sciences 85(8):348-362, 2009), removal of the reprogramming vectors by 'piggyBac' transposition Woltjen et al. (Nature 458(7239):766-770, 2009); Kaji et al. (Nature 458(7239):771-775, 2009), Cre-recombinase excisable viruses Soldner et al. (Cell 136(5):964-977, 2009), episomal vectors Yu et al. (Science 324(5928):797-801, 2009), cell-penetrating reprogramming proteins Zhou et al. (Stem Cells 4(5):381-384, 2009), mammalian artificial chromosomes Hiratsuka et al. (PLoS One 6(10):e25961, 2011) synthetically modified mRNAs Warren et al. (Scientific Reports 2:657, 2012), miRNA Anokye-Danso et al. (Cell Stem Cell 8(4):376-388, 2009); however, although some of these methods are commercially available, in general they still need to attain the reproducibility and reprogramming efficiency required for routine applications Mochiduki and Okita (Biotechnol Journal 7(6):789-797, 2012). Herein we explain, in four detailed protocols, the isolation of mouse and human somatic cells and their reprogramming into iPSC. All-encompassing instructions, not previously published in a single document, are provided for mouse and human iPSC colony isolation and derivation. Although mouse and human iPSC share similarities in the cellular reprogramming process and culture, both cell types need to be handled differently. PMID:23104133

Lorenzo, I M; Fleischer, A; Bachiller, D

2013-08-01

254

Mitochondrial Physiology and Gene Expression Analyses Reveal Metabolic and Translational Dysregulation in Oocyte-Induced Somatic Nuclear Reprogramming  

PubMed Central

While reprogramming a foreign nucleus after somatic cell nuclear transfer (SCNT), the enucleated oocyte (ooplasm) must signal that biomass and cellular requirements changed compared to the nucleus donor cell. Using cells expressing nuclear-encoded but mitochondria-targeted EGFP, a strategy was developed to directly distinguish maternal and embryonic products, testing ooplasm demands on transcriptional and post-transcriptional activity during reprogramming. Specifically, we compared transcript and protein levels for EGFP and other products in pre-implantation SCNT embryos, side-by-side to fertilized controls (embryos produced from the same oocyte pool, by intracytoplasmic injection of sperm containing the EGFP transgene). We observed that while EGFP transcript abundance is not different, protein levels are significantly lower in SCNT compared to fertilized blastocysts. This was not observed for Gapdh and Actb, whose protein reflected mRNA. This transcript-protein relationship indicates that the somatic nucleus can keep up with ooplasm transcript demands, whilst transcription and translation mismatch occurs after SCNT for certain mRNAs. We further detected metabolic disturbances after SCNT, suggesting a place among forces regulating post-transcriptional changes during reprogramming. Our observations ascribe oocyte-induced reprogramming with previously unsuspected regulatory dimensions, in that presence of functional proteins may no longer be inferred from mRNA, but rather depend on post-transcriptional regulation possibly modulated through metabolism. PMID:22693623

Esteves, Telma C.; Psathaki, Olympia E.; Pfeiffer, Martin J.; Balbach, Sebastian T.; Zeuschner, Dagmar; Shitara, Hiroshi; Yonekawa, Hiromichi; Siatkowski, Marcin; Fuellen, Georg; Boiani, Michele

2012-01-01

255

Synthetic seed production from somatic embryos of Pinus radiata  

Microsoft Academic Search

Pinus radiata is one of the most important forestry species in the southern hemisphere. This work describes the regeneration of this plant\\u000a via somatic embryogenesis from immature zygotic embryos. To improve this process, somatic embryogenic cell suspensions were\\u000a established in liquid media for the generation of material for embryo maturation. Each developmental stage of these suspensions\\u000a was characterized by microscopy

Felipe Aquea; María Josefina Poupin; José Tomás Matus; Marlene Gebauer; Consuelo Medina; Patricio Arce-Johnson

2008-01-01

256

Distribution of poly(A)-containing RNA during normal pollen development and during induced pollen embryogenesis in Hyoscyamus niger  

Microsoft Academic Search

The distribution of poly(A)-containing RNA (poly(A)+RNA) in pollen grains of Hyoscyamus niger during normal gametophytic development and embryogenic development induced by culture of anther segments was followed by in situ hybridization with (3H)- polyuridylic acid as a probe . No binding of the isotope occurred in pollen grains during the uninucleate phase of their development . Although (3H)polyuridylic acid binding

V. Raghavan

1981-01-01

257

Intergeneric somatic hybrid plants from sexually incompatible woody species: Citrus sinensis and Severinia disticha  

Microsoft Academic Search

The fusion of Citrus sinensis cv. Hamlin (sweet orange) protoplasts isolated from an embryogenic suspension culture with Severinia disticha (Philippine box orange) protoplasts isolated from epicotyl-derived callus with organogenic potential, resulted in the regeneration of allotetraploid somatic hybrid plants. Plant regeneration was a function of complementation, combining the capacity for somatic embryogenesis of C. sinensis with the organogenic ability of

J. W. Grosser; F. G. Gmitter; J. L. Chandler

1988-01-01

258

Modulatory effects of Tabebuia impetiginosa (Lamiales, Bignoniaceae) on doxorubicin-induced somatic mutation and recombination in Drosophila melanogaster  

PubMed Central

The wing Somatic Mutation and Recombination Test (SMART) in D. melanogaster was used to study genotoxicity of the medicinal plant Tabebuia impetiginosa. Lapachol (naphthoquinone) and ?-lapachone (quinone) are the two main chemical constituents of T. impetiginosa. These compounds have several biological properties. They induce apoptosis by generating oxygen-reactive species, thereby inhibiting topoisomerases (I and II) or inducing other enzymes dependent on NAD(P)H:quinone oxidoreductase 1, thus affecting cell cycle checkpoints. The SMART was used in the standard (ST) version, which has normal levels of cytochrome P450 (CYP) enzymes, to check the direct action of this compound, and in the high bioactivation (HB) version, which has a high constitutive level of CYP enzymes, to check for indirect action in three different T. impetiginosa concentrations (10%, 20% or 40% w/w). It was observed that T. impetiginosa alone did not modify the spontaneous frequencies of mutant spots in either cross. The negative results observed prompted us to study this phytotherapeuticum in association with the reference mutagen doxorubicin (DXR). In co-treated series, T. impetiginosa was toxic in both crosses at higher concentration, whereas in the HB cross, it induced a considerable potentiating effect (from ~24.0 to ~95.0%) on DXR genotoxity. Therefore, further research is needed to determine the possible risks associated with the exposure of living organisms to this complex mixture. PMID:21637695

2009-01-01

259

Siberian Sturgeon Oocyte Extract Induces Epigenetic Modifications of Porcine Somatic Cells and Improves Developmental Competence of SCNT Embryos.  

PubMed

Somatic cell nuclear transfer (SCNT) has generally demonstrated that a differentiated cell can convert into a undifferentiated or pluripotent state. In the SCNT experiment, nuclear reprogramming is induced by exposure of introduced donor nuclei to the recipient cytoplasm of matured oocytes. However, because the efficiency of SCNT still remains low, a combination of SCNT technique with the ex-ovo method may improve the normal development of SCNT embryos. Here we hypothesized that treatment of somatic cells with extracts prepared from the germinal vesicle (GV) stage Siberian sturgeon oocytes prior to their use as nuclear donor for SCNT would improve in vitro development. A reversible permeability protocol with 4 ?g/mL of digitonin for 2 min at 4°C in order to deliver Siberian sturgeon oocyte extract (SOE) to porcine fetal fibroblasts (PFFs) was carried out. As results, the intensity of H3K9ac staining in PFFs following treatment of SOE for 7 h at 18°C was significantly increased but the intensity of H3K9me3 staining in PFFs was significantly decreased as compared with the control (p<0.05). Additionally, the level of histone acetylation in SCNT embryos at the zygote stage was significantly increased when reconstructed using SOE-treated cells (p<0.05), similar to that of IVF embryos at the zygote stage. The number of apoptotic cells was significantly decreased and pluripotency markers (Nanog, Oct4 and Sox2) were highly expressed in the blastocyst stage of SCNT embryos reconstructed using SOE-treated cells as nuclear donor (p<0.05). And there was observed a better development to the blastocyst stage in the SOE-treated group (p<0.05). Our results suggested that pre-treatment of cells with SOE could improve epigenetic reprogramming and the quality of porcine SCNT embryos. PMID:25049951

Kim, So-Young; Kim, Tae-Suk; Park, Sang-Hoon; Lee, Mi-Ran; Eun, Hye-Ju; Baek, Sang-Ki; Ko, Yeoung-Gyu; Kim, Sung-Woo; Seong, Hwan-Hoo; Campbell, Keith H S; Lee, Joon-Hee

2014-02-01

260

Distribution of poly(A)-containing RNA during normal pollen development and during induced pollen embryogenesis in Hyoscyamus niger.  

PubMed

The distribution of poly(A)-containing RNA [poly(A)+RNA] in pollen grains of Hyoscyamus niger during normal gametophytic development and embryogenic development induced by culture of anther segments was followed by in situ hybridization with [3H]-polyuridylic acid as a probe. No binding of the isotope occurred in pollen grains during the uninucleate phase of their development. Although [3H]polyuridylic acid binding sites were present in the generative and vegetative cells of maturing pollen grains, they almost completely disappeared from mature grains ready to germinate. During pollen germination, poly(A)+RNA formation was transient and was due to the activity of the generative nucleus, whereas the vegetative nucleus and the sperm cells failed to interact with the applied probe. In cultured anther segments, moderate amounts of poly(A)+RNA were detected in the uninucleate, nonvacuolate, embryogenically determined pollen grains. Poly(A)+RNA accumulation in these grains was sensitive to actinomycin D, suggesting that it represents newly transcribed mRNA. After the first haploid mitosis in the embryogenically determined pollen grains, only those grains in which the generative nucleus alone or along with the vegetative nucleus accumulated poly(A)+RNA in the surrounding cytoplasm were found to divide in the embryogenic pathway. Overall, the results suggest that, in contrast to normal gametophytic development, embryogenic development in the uninucleate pollen grains of cultured anther segments of H. niger is due to the transcriptional activation of an informational type of RNA. Subsequent divisions in the potentially embryogenic binucleate pollen grains appeared to be mediated by the continued synthesis of mRNA either in the generative nucleus or in both the generative and vegetative nuclei. PMID:6166618

Raghavan, V

1981-06-01

261

Making cardiomyocytes with your chemistry set: Small molecule-induced cardiogenesis in somatic cells.  

PubMed

Cell transplantation is an attractive potential therapy for heart diseases. For example, myocardial infarction (MI) is a leading cause of mortality in many countries. Numerous medical interventions have been developed to stabilize patients with MI and, although this has increased survival rates, there is currently no clinically approved method to reverse the loss of cardiac muscle cells (cardiomyocytes) that accompanies this disease. Cell transplantation has been proposed as a method to replace cardiomyocytes, but a safe and reliable source of cardiogenic cells is required. An ideal source would be the patients' own somatic tissue cells, which could be converted into cardiogenic cells and transplanted into the site of MI. However, these are difficult to produce in large quantities and standardized protocols to produce cardiac cells would be advantageous for the research community. To achieve these research goals, small molecules represent attractive tools to control cell behavior. In this editorial, we introduce the use of small molecules in stem cell research and summarize their application to the induction of cardiogenesis in non-cardiac cells. Exciting new developments in this field are discussed, which we hope will encourage cardiac stem cell biologists to further consider employing small molecules in their culture protocols. PMID:25810812

Kim, Woong-Hee; Jung, Da-Woon; Williams, Darren Reece

2015-03-26

262

Making cardiomyocytes with your chemistry set: Small molecule-induced cardiogenesis in somatic cells  

PubMed Central

Cell transplantation is an attractive potential therapy for heart diseases. For example, myocardial infarction (MI) is a leading cause of mortality in many countries. Numerous medical interventions have been developed to stabilize patients with MI and, although this has increased survival rates, there is currently no clinically approved method to reverse the loss of cardiac muscle cells (cardiomyocytes) that accompanies this disease. Cell transplantation has been proposed as a method to replace cardiomyocytes, but a safe and reliable source of cardiogenic cells is required. An ideal source would be the patients’ own somatic tissue cells, which could be converted into cardiogenic cells and transplanted into the site of MI. However, these are difficult to produce in large quantities and standardized protocols to produce cardiac cells would be advantageous for the research community. To achieve these research goals, small molecules represent attractive tools to control cell behavior. In this editorial, we introduce the use of small molecules in stem cell research and summarize their application to the induction of cardiogenesis in non-cardiac cells. Exciting new developments in this field are discussed, which we hope will encourage cardiac stem cell biologists to further consider employing small molecules in their culture protocols.

Kim, Woong-Hee; Jung, Da-Woon; Williams, Darren Reece

2015-01-01

263

Somatic mosaicism and allele complexity induced by CRISPR/Cas9 RNA injections in mouse zygotes  

PubMed Central

Tyrosinase is the rate-limiting enzyme for the production of melanin pigmentation. In the mouse and other animals, homozygous null mutations in the Tyrosinase gene (Tyr) result in the absence of pigmentation, i.e. albinism. Here we used the CRISPR/Cas9 system to generate mono- and bi-allelic null mutations in the Tyr locus by zygote injection of two single-guide and Cas9 RNAs. Injection into C57BL/6N wild-type embryos resulted in one completely albino founder carrying two different Tyr mutations. In addition, three pigmentation mosaics and fully pigmented littermates were obtained that transmitted new mutant Tyr alleles to progeny in test crosses with albinos. Injection into Tyr heterozygous (B6CBAF1/J × FVB/NJ) zygotes resulted in the generation of numerous albinos and also mice with a graded range of albino mosaicism. Deep sequencing revealed that the majority of the albinos and the mosaics had more than two new mutant alleles. These visual phenotypes and molecular genotypes highlight the somatic mosaicism and allele complexity in founders that occurs for targeted genes during CRISPR/Cas9-mediated mutagenesis by zygote injection in mice. PMID:24984260

Yen, Shuo-Ting; Zhang, Min; Deng, Jian Min; Usman, Shireen J.; Smith, Chad N.; Parker-Thornburg, Jan; Swinton, Paul G.; Martin, James F.; Behringer, Richard R.

2014-01-01

264

Synthetic seed production from somatic embryos of Pinus radiata.  

PubMed

Pinus radiata is one of the most important forestry species in the southern hemisphere. This work describes the regeneration of this plant via somatic embryogenesis from immature zygotic embryos. To improve this process, somatic embryogenic cell suspensions were established in liquid media for the generation of material for embryo maturation. Each developmental stage of these suspensions was characterized by microscopy and their growth phases quantified. An alginate-containing medium was used as an encapsulation method for the somatic embryos that were then germinated as artificial seeds in vitro. The protocols described in this work are both useful and reliable for industrial purposes. PMID:18563583

Aquea, Felipe; Poupin, María Josefina; Matus, José Tomás; Gebauer, Marlene; Medina, Consuelo; Arce-Johnson, Patricio

2008-10-01

265

NMDA receptor mediates chronic visceral pain induced by neonatal noxious somatic stimulation.  

PubMed

NMDA receptors (NMDAR) are important in the development and maintenance of central sensitization. Our objective was to investigate the role of spinal neurons and NMDAR in the maintenance of chronic visceral pain. Neonatal rats were injected with acidic saline adjusted to pH 4.0 in the gastrocnemius muscle every other day for 12 days. In adult rats, NR1 and NR2B subunits were examined in the lumbo-sacral (LS) spinal cord. A baseline, visceromotor response (VMR) to graded colorectal distension (CRD) was recorded before and after administration of the NMDA antagonist, CGS-19755. Extracellular recordings were performed from CRD-sensitive LS spinal neurons and pelvic nerve afferents (PNA) before and after CGS-19755. Rats that received pH 4.0 saline injections demonstrated a significant increase in the expression NR2B subunits and VMR response to CRD>20 mmHg. CGS-19755 (i.v. or i.t.) had no effect in naďve rats, but significantly decreased the response to CRD in pH 4.0 saline injected rats. CGS-19755 had no effect on the spontaneous firing of SL-A, but decreased that of SL-S. Similarly, CGS-19755 attenuates the responses of SL-S neurons to CRD, but had no effect on SL-A neurons or on the response characteristics of PNA fibers. Neonatal noxious somatic stimulation results in chronic visceral hyperalgesia and sensitizes a specific subpopulation of CRD-sensitive spinal neurons. The sensitization of these SL-S spinal neurons is attenuated by the NMDAR antagonist. The results of this study suggest that spinal NMDARs play an important role in the development of hyperalgesia early in life. PMID:25281204

Miranda, Adrian; Mickle, Aaron; Bruckert, Mitchell; Kannampalli, Pradeep; Banerjee, Banani; Sengupta, Jyoti N

2014-12-01

266

Alfalfa heat shock genes are differentially expressed during somatic embryogenesis  

Microsoft Academic Search

We have isolated two cDNA clones (Mshsp18-1; Mshsp18-2) from alfalfa (Medicago sativa L.) which encode for small heat shock proteins (HSPs) belonging to the hsp17 subfamily. The predicted amino acid sequences of the two alfalfa proteins are 92% identical and a similar degree of homology (90%) can be detected between Mshsp 18-2 and the pea hsp 17. In comparison to

János Györgyey; Anton Gartner; Kinga Németh; Zoltán Magyar; Heribert Hirt; Erwin Heberle-Bors; Dénes Dudits

1991-01-01

267

Somatic embryogenesis, maturation and DNA transfer in Pinus  

E-print Network

Embryogenic callus was initiated on two types of media supplemented with auxin and cytokinin using immature zygotic embryo explants of ten different sources of slash pine (Pinus elliottii Englem.). Callus induction began after 30 days. The callus...

Marek, Kimberly Ann

1994-01-01

268

Primary and cyclic somatic embryogenesis in cassava (Manihot esculente Crantz)  

Microsoft Academic Search

Cassava is one of the major food crops in the tropics. Several of the major problems in cassava can probably only be solved by breeding with cellular and molecular techniques, e.g., the introduction of specific genes (virus resistance, protein content, quality aspects and so on). These genes can be directly applied in existing varieties of vegetatively propagated crops like cassava.

C. J. J. M. Raemakers

1993-01-01

269

Somatic embryogenesis from immature inflorescences of oil palm  

Microsoft Academic Search

Summary  Immature inflorescences of oil palm (Elaeis guineensis) var. Pisifera were inoculated onto modified MS medium containing 0.3% (w\\/v) activated charcoal and 475 M 2,4-D. After 2—3 months of culture, a hard yellow callus proliferated at the base of the shoot-like structures. The high incidence of phenolic oxidation required the use of increased levels of activated charcoal (0.5% w\\/v) and 2,4-D

J. B. Teixeira; M. R. Söndahl; E. G. Kirby

1994-01-01

270

Somatic embryogenesis and plant regeneration of Nerium oleander  

Microsoft Academic Search

Leaf explants of Nerium oleander L. produced masses of callus when both an auxin and a cytokinin were included in the medium. Leaves cultured on the B5 medium of Gamborg et al. supplemented with 2,4-dichlorophenoxyacetic acid (2,4-d; 9.05 µM) plus benzyladenine (BA; 4.4 µM) produced callus and profuse rhizogenesis was observed from callus developed from older leaves. On Murashige &

Isabel Santos; Isabel Guimarăes; Roberto Salema

1994-01-01

271

Regulation of somatic embryogenesis by plant growth regulators in sugarcane  

Microsoft Academic Search

Effect of plant growth regulators on morphogenesis was studied using callus derived from inflorescence segments of sugarcane\\u000a cv. Co-91010 and CoC-671 cultured on MS medium supplemented with 2,4-D, malt extract, L-glutamine, casein hydroly sate and\\u000a coconut water (CW). Comparison was made of different media combinations of CW (5,10%), kinetin (lmg\\/l), zeatin (0.5mg\\/l) andTDZ\\u000a (0.5mg\\/l) to study callus growth and regeneration.

P. Suprasanna; R. S. Choudhary; N. S. Desai; V. A. Bapat

2005-01-01

272

Can Body Condition and Somatic Indices be Used to Evaluate Metal-Induced Stress in Wild Small Mammals?  

PubMed Central

Wildlife is exposed to natural (e.g., food availability and quality, parasitism) and anthropogenic stressors (e.g., habitat fragmentation, toxicants). Individual variables (e.g., age, gender) affect behaviour and physiology of animals. Together, these parameters can create both great inter-individual variations in health indicators and interpretation difficulties. We investigated the relevance of body condition and somatic indices (liver, kidneys) as indicators of health status in wood mice (Apodemus sylvaticus, n?=?560) captured along a metal pollution gradient in four landscape types (30 sampling squares 500-m sided). The indices were calculated using a recently proposed standard major axis regression instead of an ordinary least square regression. After considering age and gender for the body condition index, no landscape type influence was detected in the indices. However, important index variability was observed between sampling squares; this effect was included as a random effect in linear models. After integrating all individual and environmental variables that may affect the indices, cadmium (Cd) concentrations in both the liver and kidneys were negatively related to body condition and liver indices only for individuals from highly contaminated sites. Lead in the liver was negatively related to the liver index, and Cd in kidneys was positively linked to the kidney index, potentially suggesting metal-induced stress. However, interpretation of these indices as a wildlife ecotoxicology tool should be performed with caution due to the sensitivity of potentially confounding variables (e.g., individual factors and environmental parameters). PMID:23824591

Tęte, Nicolas; Fritsch, Clémentine; Afonso, Eve; Coeurdassier, Michaël; Lambert, Jean-Claude; Giraudoux, Patrick; Scheifler, Renaud

2013-01-01

273

A source of the single-stranded DNA substrate for activation-induced deaminase during somatic hypermutation.  

PubMed

During somatic hypermutation (SHM), activation-induced deaminase (AID) mutates deoxycytidine on single-stranded DNA (ssDNA) generated by the transcription machinery, but the detailed mechanism remains unclear. Here we report a higher abundance of RNA polymerase II (Pol II) at the immunoglobulin heavy-chain variable (Igh-V) region compared with the constant region and partially transcribed Igh RNAs, suggesting a slower Pol II progression at Igh-V that could result in some early/premature transcription termination after prolonged pausing/stalling of Pol II. Knocking down RNA-exosome complexes, which could decrease premature transcription termination, leads to decreased SHM. Knocking down Spt5, which can augment premature transcription termination, leads to increase in both, SHM and the abundance of ssDNA substrates. Collectively, our data support the model that, following the reduction of Pol II progression (pausing or stalling) at the Igh-V, additional steps such as premature transcription termination are involved in providing ssDNA substrates for AID during SHM. PMID:24923561

Wang, Xiaohua; Fan, Manxia; Kalis, Susan; Wei, Lirong; Scharff, Matthew D

2014-01-01

274

Analysis of the chromosome aberrations induced by x-rays in somatic cells of Drosophila melanogaster  

Microsoft Academic Search

A technique has been perfected for enabling good microscope preparations to be obtained from the larval ganglia of Drosophila melanogaster. This system was then tested with X-rays and an extensive series of data was obtained on the chromosome aberrations induced in the various stages of the cell cycle.- The analysis of the results obtained offers the following points of interest:

M. Gatti; C. Tanzarella; G. Olivieri

1974-01-01

275

Somatic rearrangements across cancer reveal classes of samples with distinct patterns of DNA breakage and rearrangement-induced hypermutability  

E-print Network

Whole-genome sequencing using massively parallel sequencing technologies enables accurate detection of somatic rearrangements in cancer. Pinpointing large numbers of rearrangement breakpoints to base-pair resolution allows ...

Lander, Eric S.

276

Reprogramming mammalian somatic cells.  

PubMed

Somatic cell nuclear transfer (SCNT), the technique commonly known as cloning, permits transformation of a somatic cell into an undifferentiated zygote with the potential to develop into a newborn animal (i.e., a clone). In somatic cells, chromatin is programmed to repress most genes and express some, depending on the tissue. It is evident that the enucleated oocyte provides the environment in which embryonic genes in a somatic cell can be expressed. This process is controlled by a series of epigenetic modifications, generally referred to as "nuclear reprogramming," which are thought to involve the removal of reversible epigenetic changes acquired during cell differentiation. A similar process is thought to occur by overexpression of key transcription factors to generate induced pluripotent stem cells (iPSCs), bypassing the need for SCNT. Despite its obvious scientific and medical importance, and the great number of studies addressing the subject, the molecular basis of reprogramming in both reprogramming strategies is largely unknown. The present review focuses on the cellular and molecular events that occur during nuclear reprogramming in the context of SCNT and the various approaches currently being used to improve nuclear reprogramming. A better understanding of the reprogramming mechanism will have a direct impact on the efficiency of current SCNT procedures, as well as iPSC derivation. PMID:22979962

Rodriguez-Osorio, N; Urrego, R; Cibelli, J B; Eilertsen, K; Memili, E

2012-12-01

277

Comparative transcriptome analysis between somatic embryos (SEs) and zygotic embryos in cotton: evidence for stress response functions in SE development.  

PubMed

As a product of asexual reproduction in plants, the somatic embryo (SE) differentiates into a new plantlet via a zygotic embryogenesis-like process. Here, we present the phenotypic and cellular differences between SEs and zygotic embryos (ZEs) revealed by histological section scanning using three parallel development stages of the two types of embryos of cotton (Gossypium hirsutum cv. YZ1), including globular, torpedo and cotyledonary-stages. To identify the molecular characteristics of SE development in cotton, the digital gene expression system was used to profile the genes active during SE and ZE development. A total of 4242 differentially expressed genes (DEGs) were identified in at least one developmental stage. Expression pattern and functional classification analysis based on these DEGs reveals that SE development exhibits a transcriptional activation of stress responses. RT-PCR analysis further confirmed enhanced expression levels of stress-related genes in SEs than in ZEs. Experimental stress treatment, induced by NaCl and ABA, accelerated SE development and increased the transcription of genes related to stress response, in parallel with decelerated proliferation of embryogenic calluses under stress treatment. Our data reveal that SE development involves the activation of stress responses, which we suggest may regulate the balance between cell proliferation and differentiation. These results provide new insight into the molecular mechanisms of SE development and suggest strategies that can be used for regulating the developmental processes of somatic embryogenesis. PMID:24112122

Jin, Fangyan; Hu, Lisong; Yuan, Daojun; Xu, Jiao; Gao, Wenhui; He, Liangrong; Yang, Xiyan; Zhang, Xianlong

2014-02-01

278

Efficient generation human induced pluripotent stem cells from human somatic cells with Sendai-virus.  

PubMed

A few years ago, the establishment of human induced pluripotent stem cells (iPSCs) ushered in a new era in biomedicine. Potential uses of human iPSCs include modeling pathogenesis of human genetic diseases, autologous cell therapy after gene correction, and personalized drug screening by providing a source of patient-specific and symptom relevant cells. However, there are several hurdles to overcome, such as eliminating the remaining reprogramming factor transgene expression after human iPSCs production. More importantly, residual transgene expression in undifferentiated human iPSCs could hamper proper differentiations and misguide the interpretation of disease-relevant in vitro phenotypes. With this reason, integration-free and/or transgene-free human iPSCs have been developed using several methods, such as adenovirus, the piggyBac system, minicircle vector, episomal vectors, direct protein delivery and synthesized mRNA. However, efficiency of reprogramming using integration-free methods is quite low in most cases. Here, we present a method to isolate human iPSCs by using Sendai-virus (RNA virus) based reprogramming system. This reprogramming method shows consistent results and high efficiency in cost-effective manner. PMID:24798302

Choi, In Young; Lim, HoTae; Lee, Gabsang

2014-01-01

279

ONSL and OSKM cocktails act synergistically in reprogramming human somatic cells into induced pluripotent stem cells.  

PubMed

The advent of human induced pluripotent stem cells (hiPSC) is revolutionizing many research fields including cell-replacement therapy, drug screening, physiopathology of specific diseases and more basic research such as embryonic development or diseases modeling. Despite the large number of reports on reprogramming methods, techniques in use remain globally inefficient. We present here a new optimized approach to improve this efficiency. After having tested different monocistronic vectors with poor results, we adopted a polycistronic cassette encoding Thomson's cocktail OCT4, NANOG, SOX2 and LIN28 (ONSL) separated by 2A peptides. This cassette was tested in various vector backbones, based on lentivirus or retrovirus under a LTR or EF1 alpha promoter. This allowed us to show that ONSL-carrier retrovectors reprogrammed adult fibroblast cells with a much higher efficiency (up to 0.6%) than any other tested. We then compared the reprogramming efficiencies of two different polycistronic genes, ONSL and OCT4, SOX2, KLF4 and cMYC (OSKM) placed in the same retrovector backbone. Interestingly, in this context ONSL gene reprograms more efficiently than OSKM but OSKM reprograms faster suggesting that the two cocktails may reprogram through distinct pathways. By equally mixing RV-LTR-ONSL and RV-LTR-OSKM, we indeed observed a remarkable synergy, yielding a reprogramming efficiency of >2%. We present here a drastic improvement of the reprogramming efficiency, which opens doors to the development of automated and high throughput strategies of hiPSC production. Furthermore, non-integrative reprogramming protocols (i.e. mRNA) may take advantage of this synergy to boost their efficiency. PMID:24501429

Jung, Laura; Tropel, Philippe; Moal, Yohann; Teletin, Marius; Jeandidier, Eric; Gayon, Régis; Himmelspach, Christian; Bello, Fiona; André, Cécile; Tosch, Adeline; Mansouri, Ahmed; Bruant-Rodier, Catherine; Bouillé, Pascale; Viville, Stéphane

2014-06-01

280

Proteomic Analysis of Early Reprogramming Events in Murine Somatic Cells Incubated with Xenopus laevis Oocyte Extracts Demonstrates Network Associations with Induced Pluripotency Markers  

PubMed Central

Abstract The reprogramming of somatic cells into a pluripotent/embryonic-like state holds great potential for regenerative medicine, bypassing ethical issues associated with embryonic stem cells (ESCs). Numerous methods, including somatic cell nuclear transfer (SCNT), fusion to pluripotent cells, the use of cell extracts, and expression of transcription factors, have been used to reprogram cells into ES-like cells [termed induced pluripotent stem cells (iPSCs)]. This study investigated early events in the nuclei of permeabilized murine somatic cells incubated in cytoplasmic extract prepared from Xenopus laevis germinal vesicle–stage oocytes by identifying proteins that showed significant quantitative changes using proteomic techniques. A total of 69 protein spots from two-dimensional electrophoresis were identified as being significantly altered in expression after treatment, and 38 proteins were identified by tandem mass spectrometry. Network analysis was used to highlight pathway connections and interactions between these identified proteins, which were found to be involved in many functions—primarily nuclear structure and dynamics, transcription, and translation. The pluripotency markers Klf4, c-Myc, Nanog, and POU5F1 were highlighted by the interaction network analysis, as well as other compounds/proteins known to be repressed in pluripotent cells [e.g., protein kinase C (PRKC)] or enhanced during differentiation of ESCs (e.g., retinoic acid). The network analysis also indicated additional proteins and pathways potentially involved in early reprogramming events. PMID:23768116

Liddell, Susan; Campbell, Keith H.S.

2013-01-01

281

Analysis of Human and Mouse Reprogramming of Somatic Cells to Induced Pluripotent Stem Cells. What Is in the Plate?  

Microsoft Academic Search

After the hope and controversy brought by embryonic stem cells two decades ago for regenerative medicine, a new turn has been taken in pluripotent cells research when, in 2006, Yamanaka's group reported the reprogramming of fibroblasts to pluripotent cells with the transfection of only four transcription factors. Since then many researchers have managed to reprogram somatic cells from diverse origins

Stéphanie Boué; Ida Paramonov; María José Barrero; Juan Carlos Izpisúa Belmonte

2010-01-01

282

Pollen embryogenesis: atavism or totipotency?  

Microsoft Academic Search

Summary The origins of pollen embryogenesis are still in doubt. Totipotency of plant cells has traditionally been put forward as an explanation for this phenomenon but we have found this interpretation to involve some shortcomings. The pollen grain is a highly differentiated structure which should have a very reduced capability of regenerating a whole plant, whereas in some species the

F. J. Bonet; L. Azbaid; A. Olmedilla

1998-01-01

283

[Depression and somatic comorbidity].  

PubMed

Depressed persons have a higher risk of developing somatic conditions such as cardiovascular disease, diabetes and obesity. Somatic comorbidity in depressed persons may be explained by mediating mechanisms such as unhealthy lifestyle and unfavorable pathophysiological disturbances. There are alternative explanations for somatic comorbidity in depressed persons: genetic pleiotropy, iatrogenic effects, and the phenomenon 'somatic depression'. In the latter, the symptoms of depression are a consequence of clinical or subclinical somatic conditions. When treating a depressed patient, their somatic health should also be monitored. Further research is needed to examine whether specific interventions may prevent somatic comorbidity in depression. PMID:20456788

Penninx, Brenda W J H; van Dyck, Richard

2010-01-01

284

In vitro response of encapsulated somatic embryos of camellia  

Microsoft Academic Search

Somatic embryos of Camellia japonica were hydrogel encapsulated using 3% sodium alginate and 0.1 M calcium chloride to produce\\u000a synthetic seeds. Both germinability and repetitive embryogenesis capacity of the encapsulated embryos were investigated. The\\u000a frequency of in vitro germination into plants of artificial seeds was affected by various nutrient additives included in the\\u000a encapsulating matrix. The addition of Ca-free Murashige

Laura V. Janeiro; Antonio Ballester; Ana M. Vieitez

1997-01-01

285

Somatic rearrangements across cancer reveal classes of samples with distinct patterns of DNA breakage and rearrangement-induced hypermutability  

PubMed Central

Whole-genome sequencing using massively parallel sequencing technologies enables accurate detection of somatic rearrangements in cancer. Pinpointing large numbers of rearrangement breakpoints to base-pair resolution allows analysis of rearrangement microhomology and genomic location for every sample. Here we analyze 95 tumor genome sequences from breast, head and neck, colorectal, and prostate carcinomas, and from melanoma, multiple myeloma, and chronic lymphocytic leukemia. We discover three genomic factors that are significantly correlated with the distribution of rearrangements: replication time, transcription rate, and GC content. The correlation is complex, and different patterns are observed between tumor types, within tumor types, and even between different types of rearrangements. Mutations in the APC gene correlate with and, hence, potentially contribute to DNA breakage in late-replicating, low %GC, untranscribed regions of the genome. We show that somatic rearrangements display less microhomology than germline rearrangements, and that breakpoint loci are correlated with local hypermutability with a particular enrichment for transversions. PMID:23124520

Drier, Yotam; Lawrence, Michael S.; Carter, Scott L.; Stewart, Chip; Gabriel, Stacey B.; Lander, Eric S.; Meyerson, Matthew; Beroukhim, Rameen; Getz, Gad

2013-01-01

286

Reprogramming of somatic cells induced by fusion of embryonic stem cells using hemagglutinating virus of Japan envelope (HVJ-E)  

SciTech Connect

In this research, hemagglutinating virus of Japan envelope (HVJ-E) was used to reprogram somatic cells by fusion with mouse embryonic stem (ES) cells. Neomycin-resistant mouse embryonic fibroblasts (MEFs) were used as somatic cells. Nanog-overexpressing puromycin-resistant EB3 cells were used as mouse ES cells. These two cells were fused by exposing to HVJ-E and the generated fusion cells were selected by puromycin and G418 to get the stable fusion cell line. The fusion cells form colonies in feeder-free culture system. Microsatellite analysis of the fusion cells showed that they possessed genes from both ES cells and fibroblasts. The fusion cells were tetraploid, had alkali phosphatase activity, and expressed stem cell marker genes such as Pou5f1, Nanog, and Sox2, but not the fibroblast cell marker genes such as Col1a1 and Col1a2. The pluripotency of fusion cells was confirmed by their expression of marker genes for all the three germ layers after differentiation induction, and by their ability to form teratoma which contained all the three primary layers. Our results show that HVJ-E can be used as a fusion reagent for reprogramming of somatic cells.

Yue, Xiao-shan [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan) [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Department of Biomolecular Engineering, Graduate School of Bioscience and Technology, Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, Yokohama-shi, Kanagawa 226-8501 (Japan); Fujishiro, Masako [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan)] [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Toyoda, Masashi [Department of Reproductive Biology, National Institute for Child Health and Development, 2-10-1, Okura, Setagaya-ku, Tokyo 157-8535 (Japan)] [Department of Reproductive Biology, National Institute for Child Health and Development, 2-10-1, Okura, Setagaya-ku, Tokyo 157-8535 (Japan); Akaike, Toshihiro [Department of Biomolecular Engineering, Graduate School of Bioscience and Technology, Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, Yokohama-shi, Kanagawa 226-8501 (Japan)] [Department of Biomolecular Engineering, Graduate School of Bioscience and Technology, Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, Yokohama-shi, Kanagawa 226-8501 (Japan); Ito, Yoshihiro, E-mail: y-ito@riken.jp [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan) [Nano Medical Engineering Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Department of Biomolecular Engineering, Graduate School of Bioscience and Technology, Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, Yokohama-shi, Kanagawa 226-8501 (Japan)

2010-04-16

287

Somatic Cell-Induced Hyperacetylation, But Not Hypomethylation, Positively and Reversibly Affects the Efficiency of In Vitro Cloned Blastocyst Production in Cattle  

PubMed Central

Abstract 5-Aza-2?-deoxycytidine (AzC), trichostatin A (TSA), and its natural mimetic, sodium butyrate (NaB), are antineoplastic drugs that can modify the epigenetic status of donor cells prior to somatic cell nuclear transfer (SCNT). In this study, we used fibroblast cells treated with these drugs to investigate the direct and indirect effects of induced changes in DNA methylation and acetylation of the lysine 9 residue of histone H3 (H3K9). Additionally, we assayed cellular characteristics (cell growth, cell proliferation, cell cycle progression, and apoptosis) and SCNT efficiency in response to these drugs as well as monitoring these effects 24?h after removing the drugs. We observed the following: (1) AzC, TSA, and NaB all showed dose-dependent effects on different cellular characteristics; (2) TSA and NaB induced H3K9 hyperacetylation accompanied by DNA hypermethylation, whereas AzC induced DNA hypomethylation with no effect on H3K9 hyperacetylation; (3) TSA and NaB improved cloning efficiency, whereas AzC reduced it; and (4) unlike AzC, the effects of TSA and NaB on cellular characteristics and SCNT efficiency were reversed following drug removal. Our results indicate that somatic cells treated with TSA and NaB show better survival and recovery rates following the removal of these drugs. Moreover, H3K9 hyperacetylation (induced with TSA and NaB), but not DNA hypomethylation (induced with AzC), favors cloning efficiency. PMID:21919704

Jafarpour, Farnoosh; Hosseini, Sayed Morteza; Hajian, Mehdi; Forouzanfar, Mohsen; Ostadhosseini, Somayyeh; Abedi, Parvaneh; Gholami, Soghra; Ghaedi, Kamran; Gourabi, Hamid; Shahverdi, Abdol Hossein; Vosough, Ahmad Dizaj Taghi

2011-01-01

288

Somatic cell-induced hyperacetylation, but not hypomethylation, positively and reversibly affects the efficiency of in vitro cloned blastocyst production in cattle.  

PubMed

5-Aza-2'-deoxycytidine (AzC), trichostatin A (TSA), and its natural mimetic, sodium butyrate (NaB), are antineoplastic drugs that can modify the epigenetic status of donor cells prior to somatic cell nuclear transfer (SCNT). In this study, we used fibroblast cells treated with these drugs to investigate the direct and indirect effects of induced changes in DNA methylation and acetylation of the lysine 9 residue of histone H3 (H3K9). Additionally, we assayed cellular characteristics (cell growth, cell proliferation, cell cycle progression, and apoptosis) and SCNT efficiency in response to these drugs as well as monitoring these effects 24?h after removing the drugs. We observed the following: (1) AzC, TSA, and NaB all showed dose-dependent effects on different cellular characteristics; (2) TSA and NaB induced H3K9 hyperacetylation accompanied by DNA hypermethylation, whereas AzC induced DNA hypomethylation with no effect on H3K9 hyperacetylation; (3) TSA and NaB improved cloning efficiency, whereas AzC reduced it; and (4) unlike AzC, the effects of TSA and NaB on cellular characteristics and SCNT efficiency were reversed following drug removal. Our results indicate that somatic cells treated with TSA and NaB show better survival and recovery rates following the removal of these drugs. Moreover, H3K9 hyperacetylation (induced with TSA and NaB), but not DNA hypomethylation (induced with AzC), favors cloning efficiency. PMID:21919704

Jafarpour, Farnoosh; Hosseini, Sayed Morteza; Hajian, Mehdi; Forouzanfar, Mohsen; Ostadhosseini, Somayyeh; Abedi, Parvaneh; Gholami, Soghra; Ghaedi, Kamran; Gourabi, Hamid; Shahverdi, Abdol Hossein; Vosough, Ahmad Dizaj Taghi; Nasr-Esfahani, Mohammad Hossein

2011-12-01

289

Histology of Organogenic and Embryogenic Responses in Cotyledons of Somatic Embryos of Quercus suber L  

Microsoft Academic Search

In cork oak (Quercus suber L.), recurrent embryogenesis is produced in vitro through autoembryony without exogenous plant growth regulators (PGRs); secondary embryos appear on the embryo axis but seldom on cotyledons. Focusing mainly on the histological origin of neoformations, we investigated the influence of the embryo axis and exogenous PGRs on the embryogenic potential of somatic embryo cotyledons. Isolated cotyledons

Pere Puigderrajols; Cristina Celestino; Monica Suils; Mariano Toribio; Marisa Molinas

2000-01-01

290

SYCHRONIZED SOMATIC EMBRYO DEVELOPMENT IN EMBRYOGENIC SUSPENSIONS OF GRAPEVINE (MUSCADINIA ROTUNDIFOLIA SMALL AND VITIS VINIFERA L.)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The full advantages of somatic embryogenesis as a regeneration system and essential model for performing functional genomics studies and understanding molecular aspect of the ontogenesis of higher plants are demonstrated only in high-frequency, synchronous embryogenic system in liquid culture. In t...

291

Kinetic studies of embryo development and nutrient utilization in an alfalfa direct somatic embryogenic system  

Microsoft Academic Search

A method for direct somatic embryogenesis in alfalfa (Medicago falcata) is described. The time course in the development phase has been followed for fresh weight, cell density, pH, sugar uptake and embryo number and type. The method of disrupting the explant material has also been shown to influence subsequent embryo formation.

Plamen D. Denchev; Alexander I. Kuklin; Atanas I. Atanassov; Alan H. Scragg

1993-01-01

292

Class IIa Histone Deacetylases and Myocyte Enhancer Factor 2 Proteins Regulate the Mesenchymal-to-Epithelial Transition of Somatic Cell Reprogramming*  

PubMed Central

Class IIa histone deacetylases (HDACs) and myocyte enhancer factor 2 (MEF2) proteins compose a signaling module that orchestrates lineage specification during embryogenesis. We show here that this module also regulates the generation of mouse induced pluripotent stem cells by defined transcription factors. Class IIa HDACs and MEF2 proteins rise steadily during fibroblast reprogramming to induced pluripotent stem cells. MEF2 proteins tend to block the process by inducing the expression of Tgf? cytokines, which impairs the necessary phase of mesenchymal-to-epithelial transition (MET). Conversely, class IIa HDACs endeavor to suppress the activity of MEF2 proteins, thus enhancing the MET and colony formation efficiency. Our work highlights an unexpected role for a developmental axis in somatic cell reprogramming and provides new insight into how the MET is regulated in this context. PMID:23467414

Zhuang, Qiang; Qing, Xiaobing; Ying, Yue; Wu, Haitao; Benda, Christina; Lin, Jiao; Huang, Zhijian; Liu, Longqi; Xu, Yan; Bao, Xichen; Qin, Baoming; Pei, Duanqing; Esteban, Miguel A.

2013-01-01

293

A new microspore embryogenesis system under low temperature which mimics zygotic embryogenesis initials, expresses auxin and efficiently regenerates doubled-haploid plants in Brassica napus  

PubMed Central

Background Microspore embryogenesis represents a unique system of single cell reprogramming in plants wherein a highly specialized cell, the microspore, by specific stress treatment, switches its fate towards an embryogenesis pathway. In Brassica napus, a model species for this phenomenon, incubation of isolated microspores at 32°C is considered to be a pre-requisite for embryogenesis induction. Results We have developed a new in vitro system at lower temperature (18°C) to efficiently induce microspore embryogenesis throughout two different developmental pathways: one involving the formation of suspensor-like structures (52.4%) and another producing multicellular embryos without suspensor (13.1%); additionally, a small proportion of non-responsive microspores followed a gametophytic-like development (34.4%) leading to mature pollen. The suspensor-like pathway followed at 18°C involved the establishment of asymmetric identities from the first microspore division and an early polarity leading to different cell fates, suspensor and embryo development, which were formed by cells with different organizations and endogenous auxin distribution, similar to zygotic embryogenesis. In addition, a new strategy for germination of microspore derived embryos was developed for achieving more than 90% conversion of embryos to plantlets, with a predominance of spontaneous doubled haploids plants. Conclusion The present work reveals a novel mechanism for efficient microspore embryogenesis induction in B. napus using continuous low temperature treatment. Results indicated that low temperature applied for longer periods favours an embryogenesis pathway whose first division originates asymmetric cell identities, early polarity establishment and the formation of suspensor-like structures, mimicking zygotic embryogenesis. This new in vitro system provides a convenient tool to analyze in situ the mechanisms underlying different developmental pathways during the microspore reprogramming, breaking or not the cellular symmetry, the establishment of polarity and the developmental embryo patterning, which further produce mature embryos and plants. PMID:22857779

2012-01-01

294

Temperature manipulation during layer chick embryogenesis.  

PubMed

The current study investigated the effects of temperature manipulation (TM) during late embryogenesis on temperature preference, response to high environmental temperature, behavior, and performance in young layer chicks. Control (CC) embryos (n = 96) were incubated at 37.8 degrees C eggshell temperature throughout incubation. Thermally manipulated embryos (n = 96) were incubated at 37.8 degrees C eggshell temperature throughout incubation and were exposed to 40 degrees C for 4 h/d from embryonic d 14 to 18 (TM chicks). After hatch, chicks from each treatment were divided into 3 subgroups (n = 32 per group) and were subjected to a temperature preference test at d 1, 7, or 33. One day after the temperature preference test, each subgroup was exposed to 1 thermal challenge for 4 h (d 2, 40 degrees C; d 8, 40 degrees C; or d 34, 35 degrees C). Effects of TM on (fearfulness) behavior of chicks were investigated in a tonic immobility test and during home pen observations. Temperature manipulation decreased incubation time with 7 h (P < 0.0001) and body temperature at hatch with 0.2 degrees C (P = 0.002). The TM chicks preferred a lower ambient temperature in the temperature preference test (P < 0.05) and showed a higher body temperature response than CC chicks to the thermal challenge at d 2 and 8 (P < 0.05). No effects of TM on behavior and performance were observed. Because most TM studies are conducted in broilers, this study is the first attempt to unravel the effects of TM during late embryogenesis on posthatch environmental adaptation in layer chicks. The results demonstrated that effects of our TM on postnatal temperature preference and response to high environmental temperatures are only found until d 8 of age. This may suggest 1 of 3 options: a) the timing or the level, or both, of TM and duration were not at the sensitive period of embryogenesis or not sufficient, or both, respectively; b) the level of the postnatal thermal challenge was not strong enough to induce a hyperthermic response; and c) the postnatal effects of TM in layers are limited in time. PMID:20548079

Walstra, I; Ten Napel, J; Kemp, B; van den Brand, H

2010-07-01

295

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  

Microsoft Academic Search

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

S. J. Snyman; G. M. Meyer; J. M. Richards; N. Haricharan; S. Ramgareeb; B. I. Huckett

2006-01-01

296

The effect of carbohydrates and osmoticum on storage reserve accumulation and germination of Norway spruce somatic embryos.  

PubMed

Somatic embryogenesis (SE) represents a useful experimental system for studying the regulatory mechanisms of embryo development. In this study, the effect of carbohydrates and osmoticum on storage reserve accumulation and germination of Norway spruce [Picea abies (L.) Karst] somatic embryos were investigated. Using time lapse photography, we monitored development from proliferation of proembryogenic masses (PEMs) to maturation of somatic embryos in two P. abies cell lines cultured on two maturation treatments. A combination of sugar assays, metabolic and proteomic analyses were used to quantify storage reserves in the mature somatic embryos. The maturation treatment containing a nonpermeating osmoticum, polyethylene glycol (PEG, 7.5%) and maltose (3%) as the carbohydrate gave significantly high maturation and low germination frequencies of somatic embryos compared to the treatment with only 3% sucrose. Somatic embryos treated with 3% sucrose contained high levels of sucrose, raffinose and late embryogenesis abundant (LEA) proteins. These compounds are known to be involved in the acquisition of desiccation tolerance during seed development and maturation. In addition the sucrose treatment significantly increased the content of starch in the somatic embryos while the maltose and PEG treatment resulted in somatic embryos with a high content of storage proteins. The high levels of sucrose, raffinose and LEA proteins in the embryos treated with 3% sucrose suggest that sucrose may improve the germination of somatic embryos by promoting the acquisition of desiccation tolerance. PMID:23421376

Businge, Edward; Bygdell, Joakim; Wingsle, Gunnar; Moritz, Thomas; Egertsdotter, Ulrika

2013-10-01

297

Somatic mosaicism and disease.  

PubMed

The large number of cell divisions required to make a human body inevitably leads to the accumulation of somatic mutations. Such mutations cause individuals to be somatic mosaics. Recent advances in genomic technology now allow measurement of somatic diversity. Initial studies confirmed the expected high levels of somatic mutations within individuals. Going forward, the big questions concern the degree to which those somatic mutations influence disease. Theory predicts that the frequency of mutant cells should vary greatly between individuals. Such somatic mutational variability between individuals could explain much of the diversity in the risk of disease. But how variable is mosaicism between individuals in reality? What is the relation between the fraction of cells carrying a predisposing mutation and the risk of disease? What kinds of heritable somatic change lead to disease besides classical DNA mutations? What molecular processes connect a predisposing somatic change to disease? We know that predisposing somatic mutations strongly influence the onset of cancer. Likewise, neurodegenerative diseases may often begin from somatically mutated cells. If so, both neurodegeneration and cancer may be diseases of later life for which much of the risk may be set by early life somatic mutations. PMID:24937287

Frank, Steven A

2014-06-16

298

Signal molecules involved in plant embryogenesis  

Microsoft Academic Search

In plant embryogenesis, inductive interactions mediated by diffusable signal molecules are most likely of great importance. Evidence has been presented that at late globular stages in plant embryogenesis, perturbation of the polar auxin transport results in abberrant embryo morphology. Rhizobium lipooligosaccharides or Nod factors are a newly discovered class of bacterial molecules that are able to trigger initial steps in

Ed D. L. Schmidt; Anke J. Jong; Sacco C. Vries

1994-01-01

299

Preliminary research on conversion of encapsulated somatic embryos of Citrus reticulata Blanco, cv. Mandarino Tardivo di Ciaculli  

Microsoft Academic Search

Somatic embryogenesis was obtained through anther culture of Citrus reticulata, cv. Mandarino Tardivo di Ciaculli. The work was carried out to evaluate the response of somatic embryos inside a sodium\\u000a alginate coating to different storage periods, and to the effects of the germicide PPM (1 ml l?1) and the fungicide Thiophanate-methyl (100 mg l?1). The effect of these alone or in combination, added to

Germanŕ Maria Antonietta; Hafiz Ishfaq Ahmad; Micheli Maurizio; Standardi Alvaro

2007-01-01

300

Somatic embryo culture for propagation, artificial seed production, and conservation of sawara cypress ( Chamaecyparis pisifera Sieb. et Zucc.)  

Microsoft Academic Search

Somatic embryogenesis in Chamaecyparis pisifera Sieb. et Zucc. was initiated from immature seeds collected from the end of June to early July. Mass propagation through adventitious\\u000a shoot bud production from somatic embryo culture on Woody Plant (WP) medium and artificial seed production using sodium alginate\\u000a was achieved. A high bud forming index value (25.8) was obtained on medium supplemented with

Emilio Maruyama; Yoshihisa Hosoi; Katsuaki Ishii

2003-01-01

301

High-frequency embryogenesis, regeneration of broccoli ( Brassica oleracea var. italica) and analysis of genetic stability by RAPD  

Microsoft Academic Search

High-frequency somatic embryogenesis and shoot regeneration of broccoli (Brassica oleracea var. italica) were achieved. Cotyledon and hypocotyl explants from four varieties of broccoli were cultured on MS and modified MS media (mMS, supplemented with PG-96 organic components) with different combinations of growth regulator. The effects of genotypes, different explants, growth regulator combinations, organic components and AgNO3 on induction of calli

Ying Qin; Hong-Ling Li; Yang-Dong Guo

2007-01-01

302

Determination of genetic stability in long-term somatic embryogenic cultures and derived plantlets of cork oak using microsatellite markers.  

PubMed

Microsatellites were used to test genetic stability in somatic embryos (SE) of Quercus suber L. The SE were obtained by a simple somatic embryogenesis protocol: leaf explants from two adult plants (QsG0, QsG5) and from two juvenile plants (QsGM1, QsGM2) were inoculated on Murashige and Skoog (MS) medium with 2,4-dichlorophenoxyacetic acid and zeatin. Calluses with primary embryogenic structures were transferred to MSWH (MS medium without growth regulators) and SE proliferated by secondary somatic embryogenesis. High morphological heterogeneity was found among cotyledonary SE. However, converted plants looked morphologically normal with well-developed rooting systems and shoots. The genetic stability of the plant material during the somatic embryogenesis process was evaluated by using six to eight nuclear microsatellites transferred from Q. myrsinifolia Blume, Q. petraea (Matts.) Liebl. and Q. robur L. Five of eight microsatellites distinguished among the genotypes analyzed, and for QsG0, QsGM1 and QsGM2, uniform microsatellite patterns were generally observed within and between SE and the respective donor genotypes. For genotype QsG5, the same pattern was observed in all samples analyzed except one, where the mutation percentage was 2.5%. We conclude that microsatellite markers can be used to assess genetic stability of clonal materials and to determine genetic stability throughout the process of somatic embryogenesis. The simple somatic embryogenesis protocol described has potential for the commercial propagation of Q. suber because it results in a low percentage of mutations. PMID:16740490

Lopes, Tina; Pinto, Glória; Loureiro, Joăo; Costa, Armando; Santos, Conceiçăo

2006-09-01

303

Somatization in the community.  

PubMed

We examined the prevalence of somatization disorder symptoms elicited with the Diagnostic Interview Schedule in 3132 community respondents interviewed in Los Angeles by the Epidemiologic Catchment Area program. The variables age, gender, ethnic background, and the presence of a psychiatric diagnosis significantly influenced the number of somatization symptoms reported. An introductory review on conceptual and nosological aspects of somatization phenomena led to the formulation of a less-restrictive operational definition of the somatizer. We found that 4.4% of the respondents met criteria for this abridged cutoff score of somatization, whereas only 0.03% of the respondents met criteria for the full DSM-III somatization disorder diagnosis. This abridged cutoff score was associated with sociodemographic factors and psychiatric diagnosis in the direction predicted. PMID:3498454

Escobar, J I; Burnam, M A; Karno, M; Forsythe, A; Golding, J M

1987-08-01

304

Epigenetic and hormonal profile during maturation of Quercus Suber L. somatic embryos.  

PubMed

Somatic embryogenesis is a powerful alternative to conventional mass propagation of Quercus suber L. However, poor quality and incomplete maturation of somatic embryos restrict any application. Given that epigenetic and hormonal control govern many developmental stages, including maturation of zygotic embryos, global DNA methylation and abscisic acid (ABA) were analyzed during development and maturation of cork oak somatic embryos. Our results indicated that development of somatic embryos concurred with a decrease in 5-mdC. In contrast, endogenous ABA content showed a transient increase with a peak in immature E2 embryos denoting the onset of the maturation phase. A cold stratification phase was necessary for embryos to acquire germination ability, which coincided with a significant decrease in 5-mdC and ABA content. Immunohistochemical analyses showed that there was a specific spatial-temporal regulation during embryogenesis, particularly after the cold treatment. The acquisition of germination capacity concurred with a general low 5-mdC signal in the root meristem, while retention of the 5-mdC signal was mainly located in the shoot meristem and provascular tissues. Conversely, ABA immunolocalization was mainly located in the root and shoot apical meristems. Furthermore, a strong decrease in the ABA signal was observed in the root cap after the stratification treatment suggesting a role for the root cap during development of somatic embryos. These results suggest that, in addition to ABA, epigenetic control appears to play an important role for the correct maturation and subsequent germination of cork oak somatic embryos. PMID:25462078

Pérez, Marta; Viejo, Marcos; LaCuesta, Maite; Toorop, Peter; Cańal, María Jesús

2014-09-17

305

Influence of Media Components and pH on Somatic Embryo Induction in Three Genotypes of Soybean  

Microsoft Academic Search

The influence of media components on the initiation of somatic embryogenesis in three genotypes of soybean was investigated. The following genotypes were used: Iroquois, Macon, and Savoy. Media modifications included sucrose concentration, type and concentration of auxin at two pH levels, and pH level independently. Immature cotyledons were used as the source of explant. Cotyledons were placed on a medium

Nicolle Hofmann; Randall L. Nelson; Schuyler S. Korban

2004-01-01

306

High Efficiency Somatic Embrogenesis and Plant Regeneration in Suspension Cultures of an Ornamental Ginger Hybrid (Hedychium muluense x cv ‘Starburst’)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Plants were successfully regenerated via somatic embryogenesis from shoot apex-derived callus of an ornamental ginger hybrid, Hedychium muluense x cv ‘Starburst’. H. muluense is a dwarf species and ‘Starburst’ is a hybrid cultivar with white and very fragrant flowers in a circular, wheel-like arrang...

307

Protective effects of new medicinal mushroom, Grifola gargal singer (higher Basidiomycetes), on induced DNA damage in somatic cells of Drosophila melanogaster.  

PubMed

Grifola gargal is an edible mushroom with attributed antioxidant properties. Different sources of G. gargal materials, i.e., fruit bodies and mycelia grown in liquid or solid media, were used to study its potential protective capacity when somatic mutation and recombination is induced in Drosophila melanogaster using DMBA (7-12-dimethyl-benz(?)anthracene) as promutagen. Heterozygote larvae (white/white+) were grown in media with different concentrations of DMBA. Grifola gargal fruit bodies (GgFB) or mycelia from liquid culture (GgLC) or from solid culture (GgWG), i.e., biotransformed wheat kernel flour, were added to the culture media in combined treatments with DMBA. Water, DMBA solvent, or wheat flour (WF) plus DMBA solvent were used as negative controls. Larval mortality increased from 9% to 11% in negative controls to 31% to 36% in DMBA treatments. The addition of GgFB, GgLC, or GgWG materials produced a protective effect on 25 ?mol/vial DMBA-induced mortality. Mutations observed in SMART, as light spots per 100 eyes (LS/100 eyes), increased with increasing doses of DMBA; this was also true when considering the mutation incidence expressed as percentage of eyes exhibiting light spots (% eyes with LS). Interestingly, mycelia from GgFB, GgLC, or GgWG, in the presence of 25 ?mol/vial DMBA, showed lower values in SMART of both the total LS/100 eyes and the percentage of eyes with LS. Thus, Grifola gargal materials were not only nontoxic, but in combination with 25 ?mol/vial DMBA lowered the mortality induced by the promutagen and showed antimutagenic effects. Protective effects of G. gargal against DMBA are discussed in terms of the onset of desmutagenic and/or bioantimutagenic mechanisms of detoxification in the host organism, probably due to some bioactive compounds known to occur in higher mushrooms. PMID:22181846

Postemsky, Pablo Daniel; Palermo, Ana Maria; Curvetto, Néstor Raúl

2011-01-01

308

Somatization, Paranoia, and Language.  

ERIC Educational Resources Information Center

Free speech of subjects with somatization and paranoia was analyzed to identify and compare self-concept dimensions reflected in their lexical choices. The somatization disorder group conveyed a sense of negativism, distress, and preoccupation with an uncertain self-identity. The paranoid patients portrayed an artificially positive, grandiose…

Oxman, Thomas E.; And Others

1988-01-01

309

Rapid and efficient reprogramming of somatic cells to induced pluripotent stem cells by retinoic acid receptor gamma and liver receptor homolog 1  

PubMed Central

Somatic cells can be reprogrammed to induced pluripotent stem cells (iPSCs) by expressing four transcription factors: Oct4, Sox2, Klf4, and c-Myc. Here we report that enhancing RA signaling by expressing RA receptors (RARs) or by RA agonists profoundly promoted reprogramming, but inhibiting it using a RAR-? dominant-negative form completely blocked it. Coexpressing Rarg (RAR-?) and Lrh-1 (liver receptor homologue 1; Nr5a2) with the four factors greatly accelerated reprogramming so that reprogramming of mouse embryonic fibroblast cells to ground-state iPSCs requires only 4 d induction of these six factors. The six-factor combination readily reprogrammed primary human neonatal and adult fibroblast cells to exogenous factor-independent iPSCs, which resembled ground-state mouse ES cells in growth properties, gene expression, and signaling dependency. Our findings demonstrate that signaling through RARs has critical roles in molecular reprogramming and that the synergistic interaction between Rarg and Lrh1 directs reprogramming toward ground-state pluripotency. The human iPSCs described here should facilitate functional analysis of the human genome. PMID:21990348

Wang, Wei; Yang, Jian; Liu, Hui; Lu, Dong; Chen, Xiongfeng; Zenonos, Zenon; Campos, Lia S.; Rad, Roland; Guo, Ge; Zhang, Shujun; Bradley, Allan; Liu, Pentao

2011-01-01

310

Protective effect of l-carnitine against acrylamide-induced DNA damage in somatic and germ cells of mice  

PubMed Central

Recent findings of acrylamide (AA) in many common foods have sparked renewed interest in assessing human health hazards. AA was evaluated by the International Agency for Research on Cancer as probably carcinogenic to humans. For this reason, the aim of this study is to evaluate the potential genotoxic effect of AA using chromosomal aberration analysis and micronucleus (MN) test in mouse bone-marrow cells and morphological sperm abnormalities. The result of the present work indicated that treatment with a single dose of 10, 20, or 30 mg/kg b.wt. of AA for 24 h and the repeated dose of 10 mg/kg b.wt. for 1and 2 weeks induced a statistically significant increase in the percentage of chromosomal aberrations and micronuclei in bone- marrow cells. These percentages reduced significantly in all groups treated with AA and the protective agent l-carnitine. Also the results indicated that the dose 10, 20 and 30 mg/kg b.wt. of AA induced a statistically significant percentage of morphological sperm abnormalities compared with the control group. Such effect reached its maximum (7.24 ± 0.61) with the highest tested dose which reduced to (4.02 ± 0.58) in the group treated with the same dose of AA and l-carnitine. In conclusion, the results confirm the protective role of LC against the mutagenicity of AA. PMID:23961101

Alzahrani, Hind Abdullah Seed

2010-01-01

311

Locus-Specific DNA Methylation Reprogramming During Early Porcine Embryogenesis1  

PubMed Central

ABSTRACT During early mammalian embryogenesis, there is a wave of DNA demethylation postfertilization and de novo methylation around implantation. The paternal genome undergoes active DNA demethylation, whereas the maternal genome is passively demethylated after fertilization in most mammals except for sheep and rabbits. However, the emerging genome-wide DNA methylation landscape has revealed a regulatory and locus-specific DNA methylation reprogramming pattern in mammalian preimplantation embryos. Here we optimized a bisulfite sequencing protocol to draw base-resolution DNA methylation profiles of several selected genes in gametes, early embryos, and somatic tissue. We observed locus-specific DNA methylation reprogramming in early porcine embryos. First, some pluripotency genes (POU5F1 and NANOG) followed a typical wave of DNA demethylation and remethylation, whereas CpG-rich regions of SOX2 and CDX2 loci were hypomethylated throughout development. Second, a differentially methylated region of an imprint control region in the IGF2/H19 locus exhibited differential DNA methylation which was maintained in porcine early embryos. Third, a centromeric repeat element retained a moderate DNA methylation level in gametes, early embryos, and somatic tissue. The diverse DNA methylation reprogramming during early embryogenesis is thought to be possibly associated with the multiple functions of DNA methylation in transcriptional regulation, genome stability and genomic imprinting. The latest technology such as oxidative bisulfite sequencing to identify 5-hydroxymethylcytosine will further clarify the DNA methylation reprogramming during porcine embryonic development. PMID:23303676

Zhao, Ming-Tao; Rivera, Rocio M.; Prather, Randall S.

2013-01-01

312

Somatization or psychosomatic symptoms?  

PubMed

The author describes some problems emerging from the approach to and comprehension of somatization symptoms, discussing ambiguities regarding somatization seen in the current classification manuals (ICD-10 and DSM-IV). Then the author presents a case report of a man who presented with a bizarre symptom of feminization that was successfully treated with psychotherapy. The author ends with a discussion of the relationship between meaning and symptom. PMID:16508030

Avila, Lazslo Antonio

2006-01-01

313

The visceral and somatic antinociceptive effects of dihydrocodeine and its metabolite, dihydromorphine. A cross-over study with extensive and quinidine-induced poor metabolizers  

PubMed Central

Aims Dihydrocodeine is metabolized to dihydromorphine via the isoenzyme cytochrome P450 2D6, whose activity is determined by genetic polymorphism. The importance of the dihydromorphine metabolites for analgesia in poor metabolizers is unclear. The aim of this study was to assess the importance of the dihydromorphine metabolites of dihydrocodeine in analgesia by investigating the effects of dihydrocodeine on somatic and visceral pain thresholds in extensive and quinidine-induced poor metabolizers. Methods Eleven healthy subjects participated in a double-blind, randomized, placebo-controlled, four-way cross-over study comparing the effects of single doses of placebo and slow-release dihydrocodeine 60 mg with and without premedication with quinidine sulphate 50 mg on electrical, heat and rectal distension pain tolerance thresholds. Plasma concentrations and urinary excretion of dihydrocodeine and dihydromorphine were measured. Results In quinidine-induced poor metabolizers the plasma concentrations of dihydromorphine were reduced between 3 and 4 fold from 1.5 h to 13.5 h after dosing (P < 0.005) and urinary excretion of dihydromorphine in the first 12 h was decreased from 0.91% to 0.28% of the dihydrocodeine dose (P < 0.001). Dihydrocodeine significantly raised the heat pain tolerance thresholds (at 3.3 h and 5 h postdosing, P < 0.05) and the rectal distension defaecatory urge (at 3.3 h and 10 h postdosing, P < 0.02) and pain tolerance thresholds (at 3.3 h and 5 h postdosing, P < 0.05) compared with placebo. Premedication with quinidine did not change the effects of dihydrocodeine on pain thresholds, but decreased the effect of dihydrocodeine on defaecatory urge thresholds (at 1.5 h, 3.3 h and 10 h postdosing, P < 0.05). Conclusions In quinidine-induced poor metabolizers significant reduction in dihydromorphine metabolite production did not result in diminished analgesic effects of a single dose of dihydrocodeine. The metabolism of dihydrocodeine to dihydromorphine may therefore not be of clinical importance for analgesia. This conclusion must however, be confirmed with repeated dosing in patients with pain. PMID:9663813

Wilder-Smith, Clive H; Hufschmid, Edith; Thormann, Wolfgang

1998-01-01

314

Somatic CRISPR-Cas9-induced mutations reveal roles of embryonically essential dynein chains in Caenorhabditis elegans cilia.  

PubMed

Cilium formation and maintenance require intraflagellar transport (IFT). Although much is known about kinesin-2-driven anterograde IFT, the composition and regulation of retrograde IFT-specific dynein remain elusive. Components of cytoplasmic dynein may participate in IFT; however, their essential roles in cell division preclude functional studies in postmitotic cilia. Here, we report that inducible expression of the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system in Caenorhabditis elegans generated conditional mutations in IFT motors and particles, recapitulating ciliary defects in their null mutants. Using this method to bypass the embryonic requirement, we show the following: the dynein intermediate chain, light chain LC8, and lissencephaly-1 regulate retrograde IFT; the dynein light intermediate chain functions in dendrites and indirectly contributes to ciliogenesis; and the Tctex and Roadblock light chains are dispensable for cilium assembly. Furthermore, we demonstrate that these components undergo biphasic IFT with distinct transport frequencies and turnaround behaviors. Together, our results suggest that IFT-dynein and cytoplasmic dynein have unique compositions but also share components and regulatory mechanisms. PMID:25778918

Li, Wenjing; Yi, Peishan; Ou, Guangshuo

2015-03-16

315

N2O induces mitotic polyploidization in anther somatic cells and restores fertility in sterile interspecific hybrid lilies  

PubMed Central

Fertile plants undergoing male gametogenesis can be treated with nitrous oxide (N2O) gas to obtain 2n male gametes. N2O treatment is also expected to restore the fertility of interspecific hybrids through meiotic restitution or mitotic amphidiploidization. However, this technique has few applications to date, and it is un-known how N2O treatment restores fertility in sterile hybrids. To establish optimal N2O treatment conditions and determine its cytological mechanism of action, we treated various sized floral buds with N2O gas at different anther developmental stages from fertile and sterile hybrid lilies. N2O treatment using the optimal 1–4 mm floral buds induced mitotic polyploidization of male archesporial cells to produce 2n pollen in fertile hybrid lilies. In sterile hybrid lilies, N2O treatment doubled the chromosome number in male archesporial cells followed by homologous chromosome pairing and normal meiosis in pollen mother cells (PMC), resulting in restoration of pollen fertility. Backcrossing the resultant fertile pollen to Lilium × formolongi produced many triploid BC1 plants. Thus N2O treatment at the archesporial cell proliferating stage effectively overcame pollen sterility in hybrid lilies, resulting in fertile, 2n pollen grains that could produce progeny. The procedure presented here will promote interspecific or interploidy hybridization of lilies. PMID:23136469

Nukui, Shotarou; Kitamura, Satomi; Hioki, Tomoyo; Ootsuka, Hideaki; Miyoshi, Kazumitsu; Satou, Takao; Takatori, Yuka; Oomiya, Tomo; Okazaki, Keiichi

2011-01-01

316

Detection of a SERK-like gene in coconut and analysis of its expression during the formation of embryogenic callus and somatic embryos.  

PubMed

Somatic embryogenesis involves different molecular events including differential gene expression and various signal transduction pathways. One of the genes identified in early somatic embryogenesis is S OMATIC E MBRYOGENESIS R ECEPTOR-like K INASE (SERK). Cocos nucifera (L.) is one of the most recalcitrant species for in vitro regeneration, achieved so far only through somatic embryogenesis, although just a few embryos could be obtained from a single explant. In order to increase efficiency of this process we need to understand it better. Therefore, the purpose of the present work was to determine if an ortholog of the SERK gene is present in the coconut genome, isolate it and analyze its expression during somatic embryogenesis. The results showed the occurrence of a SERK ortholog referred to as CnSERK. Predicted sequence analysis showed that CnSERK encodes a SERK protein with the domains reported in the SERK proteins in other species. These domains consist of a signal peptide, a leucine zipper domain, five LRR, the Serine-Proline-Proline domain, which is a distinctive domain of the SERK proteins, a single transmembrane domain, the kinase domain with 11 subdomains and the C terminal region. Analysis of its expression showed that it could be detected in embryogenic tissues before embryo development could be observed. In contrast it was not detected or at lower levels in non-embryogenic tissues, thus suggesting that CnSERK expression is associated with induction of somatic embryogenesis and that it could be a potential marker of cells competent to form somatic embryos in coconut tissues cultured in vitro. PMID:18818928

Pérez-Núńez, M T; Souza, R; Sáenz, L; Chan, J L; Zúńiga-Aguilar, J J; Oropeza, C

2009-01-01

317

Early Zebrafish Embryogenesis Is Susceptible to Developmental TDCPP Exposure  

PubMed Central

Background: Chlorinated phosphate esters (CPEs) are widely used as additive flame retardants for low-density polyurethane foams and have frequently been detected at elevated concentrations within indoor environmental media. Objectives: To begin characterizing the potential toxicity of CPEs on early vertebrate development, we examined the developmental toxicity of four CPEs used in polyurethane foam: tris(1,3-dichloro-2-propyl) phosphate (TDCPP), tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP), and 2,2-bis(chloromethyl)propane-1,3-diyl tetrakis(2-chlorethyl) bis(phosphate) (V6). Methods: Using zebrafish as a model for vertebrate embryogenesis, we first screened the potential teratogenic effects of TDCPP, TCEP, TCPP, and V6 using a developmental toxicity assay. Based on these results, we focused on identification of susceptible windows of developmental TDCPP exposure as well as evaluation of uptake and elimination of TDCPP and bis(1,3-dichloro-2-propyl)phosphate (BDCPP, the primary metabolite) within whole embryos. Finally, because TDCPP-specific genotoxicity assays have, for the most part, been negative in vivo and because zygotic genome remethylation is a key biological event during cleavage, we investigated whether TDCPP altered the status of zygotic genome methylation during early zebrafish embryogenesis. Results: Overall, our findings suggest that the cleavage period during zebrafish embryogenesis is susceptible to TDCPP-induced delays in remethylation of the zygotic genome, a mechanism that may be associated with enhanced developmental toxicity following initiation of TDCPP exposure at the start of cleavage. Conclusions: Our results suggest that further research is needed to better understand the effects of a widely used and detected CPE within susceptible windows of early vertebrate development. PMID:23017583

McGee, Sean P.; Cooper, Ellen M.; Stapleton, Heather M.

2012-01-01

318

Vitamin C deficiency improves somatic embryo development through distinct gene regulatory networks in Arabidopsis  

PubMed Central

Changes in the endogenous ascorbate redox status through genetic manipulation of cellular ascorbate levels were shown to accelerate cell proliferation during the induction phase and improve maturation of somatic embryos in Arabidopsis. Mutants defective in ascorbate biosynthesis such as vtc2-5 contained ~70 % less cellular ascorbate compared with their wild-type (WT; Columbia-0) counterparts. Depletion of cellular ascorbate accelerated cell division processes and cellular reorganization and improved the number and quality of mature somatic embryos grown in culture by 6-fold compared with WT tissues. To gain insight into the molecular mechanisms underlying somatic embryogenesis (SE), we profiled dynamic changes in the transcriptome and analysed dominant patterns of gene activity in the WT and vtc2-5 lines across the somatic embryo culturing process. Our results provide insight into the gene regulatory networks controlling SE in Arabidopsis based on the association of transcription factors with DNA sequence motifs enriched in biological processes of large co-expressed gene sets. These data provide the first detailed account of temporal changes in the somatic embryo transcriptome starting with the zygotic embryo, through tissue dedifferentiation, and ending with the mature somatic embryo, and impart insight into possible mechanisms for the improved culture of somatic embryos in the vtc2-5 mutant line. PMID:25151615

Becker, Michael G.; Chan, Ainsley; Mao, Xingyu; Girard, Ian J.; Lee, Samantha; Elhiti, Mohamed; Stasolla, Claudio; Belmonte, Mark F.

2014-01-01

319

Metabolite profiling reveals clear metabolic changes during somatic embryo development of Norway spruce (Picea abies).  

PubMed

Progress on industrial-scale propagation of conifers by somatic embryogenesis has been hampered by the differences in developmental capabilities between cell lines, which are limiting the capture of genetic gains from breeding programs. In this study, we investigated the metabolic events occurring during somatic embryo development in Norway spruce to establish a better understanding of the fundamental metabolic events required for somatic embryo development. Three embryogenic cell lines of Norway spruce (Picea abies (L.) Karst) with different developmental capabilities were studied during somatic embryo development from proliferation of proembryogenic masses to mature somatic embryos. The three different cell lines displayed normal, aberrant and blocked somatic embryo development. Metabolite profiles from four development stages in each of the cell lines were obtained using combined gas chromatography-mass spectrometry. Multivariate discriminant analyses of the metabolic data revealed significant metabolites (P ??? 0.05) for each development stage and transition. The results suggest that endogenous auxin and sugar signaling affects initial stages of somatic embryo development. Furthermore, the results highlight the importance of a timed stress response and the presence of stimulatory metabolites during late stages of embryo development. PMID:22310018

Businge, Edward; Brackmann, Klaus; Moritz, Thomas; Egertsdotter, Ulrika

2012-02-01

320

Protocols for Callus and Somatic Embryo Initiation for Hibiscus sabdariffa L. (Malvaceae): Influence of Explant Type, Sugar, and Plant Growth Regulators  

Technology Transfer Automated Retrieval System (TEKTRAN)

A significant work on callus induction and somatic embryogenesis was realized for Hibiscus sabdariffa. Two genotypes (Hibiscus sabdariffa and Hibiscus sabdariffa var. altissima) two sugars (sucrose and glucose) and three concentrations (1 %, 2%, 3%) of each sugar, 3 explant types (root, hypocotyl, c...

321

Somatic progenitor cell vulnerability to mitochondrial DNA mutagenesis underlies progeroid phenotypes in Polg mutator mice.  

PubMed

Somatic stem cell (SSC) dysfunction is typical for different progeroid phenotypes in mice with genomic DNA repair defects. MtDNA mutagenesis in mice with defective Polg exonuclease activity also leads to progeroid symptoms, by an unknown mechanism. We found that Polg-Mutator mice had neural (NSC) and hematopoietic progenitor (HPC) dysfunction already from embryogenesis. NSC self-renewal was decreased in vitro, and quiescent NSC amounts were reduced in vivo. HPCs showed abnormal lineage differentiation leading to anemia and lymphopenia. N-acetyl-L-cysteine treatment rescued both NSC and HPC abnormalities, suggesting that subtle ROS/redox changes, induced by mtDNA mutagenesis, modulate SSC function. Our results show that mtDNA mutagenesis affected SSC function early but manifested as respiratory chain deficiency in nondividing tissues in old age. Deletor mice, having mtDNA deletions in postmitotic cells and no progeria, had normal SSCs. We propose that SSC compartment is sensitive to mtDNA mutagenesis, and that mitochondrial dysfunction in SSCs can underlie progeroid manifestations. PMID:22225879

Ahlqvist, Kati J; Hämäläinen, Riikka H; Yatsuga, Shuichi; Uutela, Marko; Terzioglu, Mügen; Götz, Alexandra; Forsström, Saara; Salven, Petri; Angers-Loustau, Alexandre; Kopra, Outi H; Tyynismaa, Henna; Larsson, Nils-Göran; Wartiovaara, Kirmo; Prolla, Tomas; Trifunovic, Aleksandra; Suomalainen, Anu

2012-01-01

322

Using SomaticSniper to Detect Somatic Single Nucleotide Variants  

PubMed Central

Detecting somatic single nucleotide variants (SNVs) is an essential component of cancer research with next generation sequencing data. This protocol describes how to run the SomaticSniper somatic SNV detector and then filter the output to eliminate most false positives. It also includes support protocols detailing the compilation of the software. PMID:25431635

Larson, David E.; Abbott, Travis E.; Wilson, Richard K.

2014-01-01

323

Somatic mutation theory.  

PubMed

The evidence is reviewed that supports the role of genetic lesions in carcinogenesis; such lesions may be initiating events in the multistep process leading to clinically detectable tumor. Other possible manifestations of alterations in the hereditary material of somatic cells are discussed; DNA damage may lead to benign tumors responsible for atherosclerosis, to neurological deterioration, and to senescence of the individual. During embryonal development, transplacental mutagens may cause somatic mosaicism in the fetus, which may manifest as congenital malformations, spontaneous abortions, and childhood cancers. PMID:7463528

Sorsa, M

1980-01-01

324

Somatic polymorphism and seed dispersal  

Microsoft Academic Search

SOMATIC seed polymorphism is the production of seeds of different morphologies or behaviour on different parts of the same plant and is a somatic differentiation rather than the result of genetic segregation1. This phenomenon appears to be confined to a limited number of families of higher plants (for example, Cruciferae, Compositae, Chenopodiaceae, Gramineae). Seed produced within a somatic polymorphism may

Anne E. Sorensen

1978-01-01

325

Shusterman on Somatic Experience  

ERIC Educational Resources Information Center

Richard Shusterman's "Body Consciousness" aims at formulating a theory of somaesthetics and somatic experience. There has indeed been a growing interest in the role of the body in experience. Shusterman examines the arguments of six important writers who have been influential in this discussion. The emphasis on the body is natural for a…

Maattanen, Pentti

2010-01-01

326

Stimulation of Activin A\\/Nodal signaling is insufficient to induce definitive endoderm formation of cord blood-derived unrestricted somatic stem cells  

Microsoft Academic Search

Introduction  Unrestricted somatic stem cells (USSC) derived from umbilical cord blood are an attractive alternative to human embryonic\\u000a stem cells (hESC) for cellular therapy. USSC are capable of forming cells representative of all three germ line layers. The\\u000a aim of this study was to determine the potential of USSC to form definitive endoderm following induction with Activin A, a\\u000a protein known

Caitlin E Filby; Robert Williamson; Peter van Kooy; Alice Pébay; Mirella Dottori; Ngaire J Elwood; Faten Zaibak

2011-01-01

327

Patterns of Gene Expression in Drosophila Embryogenesis  

NSDL National Science Digital Library

A new image database of gene expression patterns in Drosophila embryogenesis is now available from the Berkeley Drosophila Genome Project (BDGP), a consortium of the Drosophila Genome Center. The BDGP team used "high throughput 96-well plate RNA in situ protocol to determine patterns of gene expression during embryogenesis for Drosophila genes represented in non-redundant sets of Drosophila ESTs DGC1 and DGC2." The entire set of image, microarray, and annotation data may be browsed or searched from this Web site. As of October 4, 2002, 1354 gene expressions have been documented with 25,263 digital photographs, with many more additions expected. This site also provides a useful FAQs page.

328

Selection of Norway spruce somatic embryos by computer vision  

NASA Astrophysics Data System (ADS)

A computer vision system was developed for the classification of plant somatic embryos. The embryos are in a Petri dish that is transferred with constant speed and they are recognized as they pass a line scan camera. A classification algorithm needs to be installed for every plant species. This paper describes an algorithm for the recognition of Norway spruce (Picea abies) embryos. A short review of conifer micropropagation by somatic embryogenesis is also given. The recognition algorithm is based on features calculated from the boundary of the object. Only part of the boundary corresponding to the developing cotyledons (2 - 15) and the straight sides of the embryo are used for recognition. An index of the length of the cotyledons describes the developmental stage of the embryo. The testing set for classifier performance consisted of 118 embryos and 478 nonembryos. With the classification tolerances chosen 69% of the objects classified as embryos by a human classifier were selected and 31$% rejected. Less than 1% of the nonembryos were classified as embryos. The basic features developed can probably be easily adapted for the recognition of other conifer somatic embryos.

Hamalainen, Jari J.; Jokinen, Kari J.

1993-05-01

329

Defined nuclear changes accompany the reprogramming of the microspore to embryogenesis.  

PubMed

The switch of the gametophytic developmental program toward pollen embryogenesis to form a haploid plant represents an important alternative for plant breeding. In the present study, the switch of the gametophytic developmental program toward a sporophytic pathway, "embryogenesis," has been studied in three different plant species, Brassica, tobacco, and pepper. The switch has been induced by stress (heat shock) at the very responsive stage of the microspore, which is the vacuolate period. As a result, the cell nucleus undergoes striking structural changes with regard to late gametophytic development, including alterations of biosynthetic activities and proliferative activity. An enrichment in HSP70 heat-shock protein and in the presence of Ntf6-MAP kinase was observed after inductive treatment in the nuclei during early embryogenesis. This apparently reflected the possible roles of these proteins, specifically the protective role of HSP70 for the nuclear machinery, and signal transduction of Ntf6-MAPK for the entry of cells into proliferation. Importantly, the observed nuclear changes were similar in the three species investigated and represented convenient markers for early monitoring of embryogenesis and selection purposes for obtaining double-haploid plants in plant breeding. PMID:10806072

Testillano, P S; Coronado, M J; Seguí, J M; Domenech, J; González-Melendi, P; Raska, I; Risueńo, M C

2000-04-01

330

Periderm prevents pathological epithelial adhesions during embryogenesis  

PubMed Central

Appropriate development of stratified, squamous, keratinizing epithelia, such as the epidermis and oral epithelia, generates an outer protective permeability barrier that prevents water loss, entry of toxins, and microbial invasion. During embryogenesis, the immature ectoderm initially consists of a single layer of undifferentiated, cuboidal epithelial cells that stratifies to produce an outer layer of flattened periderm cells of unknown function. Here, we determined that periderm cells form in a distinct pattern early in embryogenesis, exhibit highly polarized expression of adhesion complexes, and are shed from the outer surface of the embryo late in development. Mice carrying loss-of-function mutations in the genes encoding IFN regulatory factor 6 (IRF6), I?B kinase-? (IKK?), and stratifin (SFN) exhibit abnormal epidermal development, and we determined that mutant animals exhibit dysfunctional periderm formation, resulting in abnormal intracellular adhesions. Furthermore, tissue from a fetus with cocoon syndrome, a lethal disorder that results from a nonsense mutation in IKKA, revealed an absence of periderm. Together, these data indicate that periderm plays a transient but fundamental role during embryogenesis by acting as a protective barrier that prevents pathological adhesion between immature, adhesion-competent epithelia. Furthermore, this study suggests that failure of periderm formation underlies a series of devastating birth defects, including popliteal pterygium syndrome, cocoon syndrome, and Bartsocas-Papas syndrome. PMID:25133425

Richardson, Rebecca J.; Hammond, Nigel L.; Coulombe, Pierre A.; Saloranta, Carola; Nousiainen, Heidi O.; Salonen, Riitta; Berry, Andrew; Hanley, Neil; Headon, Denis; Karikoski, Riitta; Dixon, Michael J.

2014-01-01

331

Periderm prevents pathological epithelial adhesions during embryogenesis.  

PubMed

Appropriate development of stratified, squamous, keratinizing epithelia, such as the epidermis and oral epithelia, generates an outer protective permeability barrier that prevents water loss, entry of toxins, and microbial invasion. During embryogenesis, the immature ectoderm initially consists of a single layer of undifferentiated, cuboidal epithelial cells that stratifies to produce an outer layer of flattened periderm cells of unknown function. Here, we determined that periderm cells form in a distinct pattern early in embryogenesis, exhibit highly polarized expression of adhesion complexes, and are shed from the outer surface of the embryo late in development. Mice carrying loss-of-function mutations in the genes encoding IFN regulatory factor 6 (IRF6), I?B kinase-? (IKK?), and stratifin (SFN) exhibit abnormal epidermal development, and we determined that mutant animals exhibit dysfunctional periderm formation, resulting in abnormal intracellular adhesions. Furthermore, tissue from a fetus with cocoon syndrome, a lethal disorder that results from a nonsense mutation in IKKA, revealed an absence of periderm. Together, these data indicate that periderm plays a transient but fundamental role during embryogenesis by acting as a protective barrier that prevents pathological adhesion between immature, adhesion-competent epithelia. Furthermore, this study suggests that failure of periderm formation underlies a series of devastating birth defects, including popliteal pterygium syndrome, cocoon syndrome, and Bartsocas-Papas syndrome. PMID:25133425

Richardson, Rebecca J; Hammond, Nigel L; Coulombe, Pierre A; Saloranta, Carola; Nousiainen, Heidi O; Salonen, Riitta; Berry, Andrew; Hanley, Neil; Headon, Denis; Karikoski, Riitta; Dixon, Michael J

2014-09-01

332

Does DNA repair occur during somatic hypermutation?  

PubMed Central

Activation-induced deaminase (AID) initiates a flood of DNA damage in the immunoglobulin loci, leading to abasic sites, single-strand breaks and mismatches. It is compelling that some proteins in the canonical base excision and mismatch repair pathways have been hijacked to increase mutagenesis during somatic hypermutation. Thus, the AID-induced mutagenic pathways involve a mix of DNA repair proteins and low fidelity DNA polymerases to create antibody diversity. In this review, we analyze the roles of base excision repair, mismatch repair, and mutagenesis during somatic hypermutation of rearranged variable genes. The emerging view is that faithful base excision repair occurs simultaneously with mutagenesis, whereas faithful mismatch repair is mostly absent. PMID:22728014

Saribasak, Huseyin; Gearhart, Patricia J.

2012-01-01

333

Transcript Profiling and Identification of Molecular Markers for Early Microspore Embryogenesis in Brassica napus1[W][OA  

PubMed Central

Isolated microspores of Brassica napus are developmentally programmed to form gametes; however, microspores can be reprogrammed through stress treatments to undergo appropriate divisions and form embryos. We are interested in the identification and isolation of factors and genes associated with the induction and establishment of embryogenesis in isolated microspores. Standard and normalized cDNA libraries, as well as subtractive cDNA libraries, were constructed from freshly isolated microspores (0 h) and microspores cultured for 3, 5, or 7 d under embryogenesis-inducing conditions. Library comparison tools were used to identify shifts in metabolism across this time course. Detailed expressed sequence tag analyses of 3 and 5 d cultures indicate that most sequences are related to pollen-specific genes. However, semiquantitative and real-time reverse transcription-polymerase chain reaction analyses at the initial stages of embryo induction also reveal expression of embryogenesis-related genes such as BABYBOOM1, LEAFY COTYLEDON1 (LEC1), and LEC2 as early as 2 to 3 d of microspore culture. Sequencing results suggest that embryogenesis is clearly established in a subset of the microspores by 7 d of culture and that this time point is optimal for isolation of embryo-specific expressed sequence tags such as ABSCISIC ACID INSENSITIVE3, ATS1, LEC1, LEC2, and FUSCA3. Following extensive polymerase chain reaction-based expression profiling, 16 genes were identified as unequivocal molecular markers for microspore embryogenesis in B. napus. These molecular marker genes also show expression during zygotic embryogenesis, underscoring the common developmental pathways that function in zygotic and gametic embryogenesis. The quantitative expression values of several of these molecular marker genes are shown to be predictive of embryogenic potential in B. napus cultivars (e.g. ‘Topas’ DH4079, ‘Allons,’ ‘Westar,’ ‘Garrison’). PMID:17384168

Malik, Meghna R.; Wang, Feng; Dirpaul, Joan M.; Zhou, Ning; Polowick, Patricia L.; Ferrie, Alison M.R.; Krochko, Joan E.

2007-01-01

334

Changes in the 2-DE protein profile during zygotic embryogenesis in the Brazilian Pine (Araucaria angustifolia).  

PubMed

Araucaria angustifolia is the only native conifer of economic importance in the Brazilian Atlantic Rainforest. Due to a clear-cutting form of exploitation this species has received the status of vulnerable. The aim of this work was to investigate and characterize changes in protein expression profile during seed development of this endangered species. For this, the proteome of developing seeds was characterized by 2-DE and LC-MS/MS. Ninety six proteins were confidently identified and classified according to their biological function and expression profile. Overaccumulated proteins in early seed development indicated a higher control on oxidative stress metabolism during this phase. In contrast, highly expressed proteins in late stages revealed an active metabolism, leading to carbon assimilation and storage compounds accumulation. Comprehensive protein expression profiles and identification of overaccumulated proteins provide new insights into the process of embryogenesis in this recalcitrant species. Considerations on the improvement and control of somatic embryogenesis through medium manipulation and protein markers screening using data generated are also discussed. PMID:19367732

Balbuena, Tiago S; Silveira, Vanildo; Junqueira, Magno; Dias, Leonardo L C; Santa-Catarina, Claudete; Shevchenko, Andrej; Floh, Eny I S

2009-04-13

335

Gamete derivation from embryonic stem cells, induced pluripotent stem cells or somatic cell nuclear transfer-derived embryonic stem cells: state of the art.  

PubMed

Generating gametes from pluripotent stem cells (PSCs) has many scientific justifications and several biomedical rationales. Here, we consider several strategies for deriving gametes from PSCs from mice and primates (human and non-human) and their anticipated strengths, challenges and limitations. Although the 'Weismann barrier', which separates the mortal somatic cell lineages from the potentially immortal germline, has long existed, breakthroughs first in mice and now in humans are artificially creating germ cells from somatic cells. Spermatozoa with full reproductive viability establishing multiple generations of seemingly normal offspring have been reported in mice and, in humans, haploid spermatids with correct parent-of-origin imprints have been obtained. Similar progress with making oocytes has been published using mouse PSCs differentiated in vitro into primordial germ cells, which are then cultured after xenografting reconstructed artificial ovaries. Progress in making human oocytes artificially is proving challenging. The usefulness of these artificial gametes, from assessing environmental exposure toxicity to optimising medical treatments to prevent negative off-target effects on fertility, may prove invaluable, as may basic discoveries on the fundamental mechanisms of gametogenesis. PMID:25472048

Easley, Charles A; Simerly, Calvin R; Schatten, Gerald

2014-12-01

336

Arabinogalactan proteins are essential in somatic embryogenesis of Daucus carota L  

Microsoft Academic Search

Daucus carota L. cell lines secrete a characteristic set of arabinogalactan proteins (AGPs) into the medium. The composition of this set of AGPs changes with the age of the culture, as can be determined by crossed electrophoresis with the specific AGP-binding agent, ß-glucosyl Yariv reagent. Addition of AGPs isolated from the medium of a non-embryogenic cell line to an expiant

Marc Kreuger; Gerrit-Jan van Hoist

1993-01-01

337

Characterization of a gene that is expressed early in somatic embryogenesis of Daucus carota  

Microsoft Academic Search

lhe EMB-1 mRNA of carrot (Daucus carota) was isolated as an embryo abundant cDNA clone (T.H. Ulrich, E.S. Wurtele, B.J. Nikolau (1990) Nucleic Acids Res 18: 2826). Northern analyses of RNA isolated from embryos, cultured cells, and a variety of vege- tative organs indicate that the EMB-1 mRNA specifically accumu- lates in embryos, beginning at the early stages of embryo

Eve Syrkin Wurtele; Huiqing Wang; SaDly Durgerian; Basil J. Nikolau; Thomas H. Ulrich

1993-01-01

338

Arabinogalactan-protein epitopes in somatic embryogenesis of Daucus carota L  

Microsoft Academic Search

Two monoclonal antibodies (ZUM 15 and ZUM 18) directed against carrot (Daucus carota L.) seed arabinogalactan proteins (AGPs) were used to isolate specific AGP fractions. For both carrot and tomato (Lycopersicon esculentum Mill.) seed AGPs analyzed by crossedelectrophoresis, the ZUM 15 and ZUM 18 AGP fractions showed one identical peak. However, the Rf values for the two species were different:

Marc Kreuger; Gerrit-Jan van Hoist

1995-01-01

339

Plantlet regeneration via somatic embryogenesis from subcultured callus of mature embryos of Picea abies (Norway spruce)  

Microsoft Academic Search

Summary  Embryogenic callus was initiated from radicles of mature embryos removed from imbibed seeds (24 h). Embryogenic and other\\u000a nonembryogenic types of callus proliferated on a modified half-strength Murashige-Skoog medium (MS) basal medium (BM) supplemented\\u000a withmyo-inositol, casein hydrolysate (CH), L-glutamine (gln) and growth regulators kinetin (KN), N6-benzyladenine (BAP) each (2010?6\\u000a M), 2,4-dichlorophenoxyacetic acid (2,4-D) (5010?6\\u000a M) Embryogenic callus bearing suspensor-like cells

Pramod K. Gupta; Don J. Durzan

1986-01-01

340

Somatic embryogenesis and plant regeneration from immature zygotic embryos of Japanese larch (Larix leptolepis)  

Microsoft Academic Search

Embryogenic tissue was initiated using LM, LP and MS media from open-pollinated immature embryos of Larix leptolepis. The\\u000a initiation frequency varied with collection dates. The highest frequencies of embryogenic tissue initiation (60, 67 and 59%\\u000a on LM, LP and MS media, respectively) were observed from cones collected on July 30. At this time, all the excised embryos\\u000a were at the

Yong Wook Kim; Yang Youn; Eu Rae Noh; Joon Chul Kim

1998-01-01

341

Plant regeneration via somatic embryogenesis from protoplasts of six plant species related to Citrus  

Microsoft Academic Search

Protoplasts isolated from embryogenic callus of Fortunella polyandra (Ridl.), Atalantia bilocularis (Pieree ex Guill.), Hesperethusa crenulata (Roxb.), Glycosmis pentaphylla (Retz.) Corr., Triphasia trifolia (Burm. f.) P. Wils. and Murraya koenigii (L.) Spreng. were cultured in MT (Murashige and Tucker 1969) basal medium containing 5% sucrose supplemented with 0.0, 0.001, 0.01, 0.1 or 1.0 mg l-1 BA and 0.6 M sorbitol.

Hasan Basri Jumin; Nobumasa Nito

1996-01-01

342

Y.-S. ParkConifer somatic embryogenesis in clonal forestry Original article  

E-print Network

and genetic stability of clones is re- viewed, using white spruce (Picea glauca) and eastern white pine (Pinus en utilisant comme espèces modèles l'épinette blanche (Picea glauca) et le pin blanc (Pinus strobus

Paris-Sud XI, Université de

343

INDUCTION OF SOMATIC EMBRYOGENESIS IN O'HENRY CULTIVAR OF PEACH (PRUNUS PERSICA)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The peach industry plays an important role in the agricultural economy of the southeastern United States, annually producing 35% of the American peach crop. Peach tree short life (PTSL) syndrome results in the drastic decline in peach tree population and orchard longevity. It prematurely kills trees...

344

Effect of weightlessness conditions on the somatic embryogenesis in the culture of carrot cells  

NASA Technical Reports Server (NTRS)

A carrot cell culture seeded in Petri dishes in the United States and transported to the USSR was subjected to weightlessness for 20 days during the flight of Kosmos 782. The controls were cultures placed on a centrifuge (1 g) inside the satellite and cultures left on ground in the U.S.S.R. and the United States. A count of structures in the dishes after the flight showed that the number of developing embryonic structures and the extent of their differentiation in weightlessness did not reliably differ from the number and extent of differentiation in structures developed on the ground. Structures with long roots developed in weightlessness. Analysis of the root zones showed that these roots differed by the increased size of the zone of differentiated cells. The increased size of the zones of differentiated cells can indicate earlier development of embryonic structures.

Butenko, R. G.; Dmitriyeva, N. N.; Ongko, V.; Basyrova, L. V.

1977-01-01

345

Rapid transformation and regeneration of alfalfa (Medicago falcata L.) via direct somatic embryogenesis  

Microsoft Academic Search

Two simple, rapid and efficient protocols for theregeneration of transformed tetraploid lines ofalfalfa (Medicago falcata L.) have beendeveloped and compared. Leaf explants fromembryogenic lines 47\\/1-150 and 47\\/1-5 were inoculatedwith Agrobacterium tumefaciens containingconstructs carrying the nptII selectable markergene and promoter:gusA gene fusions under thecontrol of the CaMV 35S or Arabidopsis cdc2a,CycB1 and CycA2 promoters. In the firstregeneration system (the MSH system),

C. Y. Shao; E. Russinova; A. Iantcheva; A. Atanassov; A. McCormac; D. F. Chen; M. C. Elliott; A. Slater

2000-01-01

346

Somatic embryogenesis of carrot in hormone-free medium: external pH control over morphogenesis  

NASA Technical Reports Server (NTRS)

Cultures of preglobular stage proembryos (PGSPs) were initiated from mechanically wounded mature zygotic embryos of carrot, Daucus carota, on a hormone-free, semisolid medium. These PGSPs have been maintained and multiplied for extended periods without their progression into later embryo stages on the same hormone-free medium containing 1 mM NH4+ as the sole nitrogen source. Sustained maintenance of cultures comprised exclusively of PGSPs was dependent on medium pH throughout the culture period. Best growth and multiplication of PGSP cultures occurred when the pH of unbuffered, hormone-free medium fell from 4.5 to 4 over a 2-week period or when buffered medium was titrated to pH 4. If the hormone-free medium was buffered to sustain a pH at or above 4.5, PGSPs developed into later embryo stages. Maintenance with continuous multiplication of PGSPs occurred equally well on medium containing NH4+ or NH4+ and NO3-, but growth was poor with NO3- alone. Additional observations on the effects of medium components such as various nitrogen sources and levels, sucrose concentration, semisolid supports, type of buffer, borate concentration, activated charcoal, and initial pH that permit optimum maintenance of the PGSPs or foster their continued developmental progression into mature embryos and plantlets are reported. The influence of the pH of the hormone-free medium as a determinant in maintaining cultures as PGSPs or allowing their continued embryonic development are unequivocally demonstrated by gross morphology, scanning electron microscopy, and histological preparations.

Smith, D. L.; Krikorian, A. D.

1990-01-01

347

Somatic Embryogenesis of Pine Species: From Functional Genomics to Plantation Forestry  

Microsoft Academic Search

Several economically important tree species belong to the genus Pinus\\u000a and many of them form the ecological base of forest ecosystems. Pine wood is an important raw material\\u000a for the forest industry and many of the pine species have been involved in conventional tree improvement\\u000a programmes. A lot of effort has been made in the development of vegetative propagation methods,\\u000a especially

Hely Häggman; Jaana Vuosku; Tytti Sarjala; Anne Jokela; Karoliina Niemi

348

Somatic embryogenesis and somaclonal variation in Norway spruce: morphogenetic, cytogenetic and molecular approaches  

Microsoft Academic Search

Four embryogenic clones of Norway spruce have been subcultivated and observed over several years to determine the evolution\\u000a of production of mature embryos and to assess the quality of the embryos produced. A wide range of intraclonal quantitative\\u000a and qualitative variability has been observed within this production. Certain morphologic deviations appeared at the immature\\u000a stage and after maturation, such as

J.-L. Fourré; P. Berger; L. Niquet; P. André

1997-01-01

349

Somatic embryogenesis and massive shoot regeneration from immature embryo explants of tef.  

PubMed

Tef (Eragrostis tef) provides a major source of human nutrition in the Horn of Africa, but biotechnology has had little impact on its improvement to date. Here, we report the elaboration of an in vitro regeneration protocol, based on the use of immature zygotic embryos as explant. Explant size was an important determinant of in vitro regeneration efficiency, as was the formulation of the culture medium. Optimal results were obtained by culturing 0.2-0.35?mm embryo explants on a medium containing KBP minerals, 9.2-13.8??M 2,4-dichlorophenoxyacetic acid, 6?mM glutamine, and 0.5% Phytagel. Although this protocol was effective for both the improved cultivar "DZ-01-196" and the landrace "Fesho", the former produced consistently more embryogenic tissue and a higher number of regenerants. An average of more than 2,800 shoots could be obtained from each "DZ-01-196" explant after 12 weeks of in vitro culture. These shoots readily formed roots, and plantlets transferred to soil were able to develop into morphologically normal, fertile plants. This regeneration and multiplication system should allow for the application of a range of biotechnological methods to tef. PMID:22028975

Gugsa, Likyelesh; Kumlehn, Jochen

2011-01-01

350

Embryogenesis and plant regeneration of pakchoi ( Brassica rapa L. ssp. chinensis) via in vitro isolated microspore culture  

Microsoft Academic Search

Isolated microspores of various populations of three varieties of the Chinese cabbage pakchoi (Brassica rapa ssp. chinensis) were cultivated in vitro on NLN82 medium (Lichter 1982) and embryos and plantlets obtained with nine cultivars. The best embryo yield per bud was 57.4. A 33°C one day heat treatment was generally necessary to induce embryogenesis. Analysis of ploidy level through flow

Ming Qing Cao; Yan Li; Fan Liu; Claire Doré

1994-01-01

351

Discovery of genes expressed in Hydra embryogenesis.  

PubMed

Hydra's remarkable capacity to regenerate, to proliferate asexually by budding, and to form a pattern de novo from aggregates allows studying complex cellular and molecular processes typical for embryonic development. The underlying assumption is that patterning in adult hydra tissue relies on factors and genes which are active also during early embryogenesis. Previously, we reported that in Hydra the timing of expression of conserved regulatory genes, known to be involved in adult patterning, differs greatly in adults and embryos (Fröbius, A.C., Genikhovich, G., Kürn, U., Anton-Erxleben, F. and Bosch, T.C.G., 2003. Expression of developmental genes during early embryogenesis of Hydra. Dev. Genes Evol. 213, 445-455). Here, we describe an unbiased screening strategy to identify genes that are relevant to Hydra vulgaris embryogenesis. The approach yielded two sets of differentially expressed genes: one set was expressed exclusively or nearly exclusively in the embryos, while the second set was upregulated in embryos in comparison to adult polyps. Many of the genes identified in hydra embryos had no matches in the database. Among the conserved genes upregulated in embryos is the Hydra orthologue of Embryonic Ectoderm Development (HyEED). The expression pattern of HyEED in developing embryos suggests that interstitial stem cells in Hydra originate in the endoderm. Importantly, the observations uncover previously unknown differences in genes expressed by embryos and polyps and indicate that not only the timing of expression of developmental genes but also the genetic context is different in Hydra embryos compared to adults. PMID:16337937

Genikhovich, Grigory; Kürn, Ulrich; Hemmrich, Georg; Bosch, Thomas C G

2006-01-15

352

Genetic Regulatory Networks in Embryogenesis and Evolution  

NASA Technical Reports Server (NTRS)

The article introduces a series of papers that were originally presented at a workshop titled Genetic Regulatory Network in Embryogenesis and Evaluation. Contents include the following: evolution of cleavage programs in relationship to axial specification and body plan evolution, changes in cell lineage specification elucidate evolutionary relations in spiralia, axial patterning in the leech: developmental mechanisms and evolutionary implications, hox genes in arthropod development and evolution, heterochronic genes in development and evolution, a common theme for LIM homeobox gene function across phylogeny, and mechanisms of specification in ascidian embryos.

1998-01-01

353

Embryogenesis of brassica rapa l. under clinorotation  

NASA Astrophysics Data System (ADS)

Investigation of reproductive development of higher plants in spaceflight represents scientific interest first of all with the necessity to work out the plant space technologies for creation of controlled life-support systems. In such systems mainly the higher plants are considered to be an important component that makes it necessary to obtain the several generations of higher plants with their full ontogenesis. As a rule, seeds obtained in three species of the higher plants in a series of experiments differ from the control by some parameters (Merkis, Laurinavichius, 1983; Musgrave et al., 1998; 2000; Levinskikh et all. 1999; Stankovich et al., 2002). It was shown, that immature embryos generated in microgravity were at a range of developmental stage, while the ground control embryos had all reached the premature stage of development (Kuang et al., 2003). Besides, the distinctions in a degree of nutrient substances accumulation in them were revealed (Kuang et al., 2000). Therefore, the elucidation of the possible reasons for distortion of plant reproduction in microgravity demands the further research. In this study we examined embryogenesis of higher plant Brassica rapa L. with an application of slow horizontal clinostats, that allows to deprive the plants the opportunity to perceive the gravitational stimulus. Some plants were clinorotated from the moment sowing of seeds; in other series the experiment plants were placed on clinostats after formation of flower buds. Temporal fixation of the material was used in these experiments, which allow to obtain material for studying of consecutive stages of embryogenesis. The development of 2-21 day-old embryos was studied. Comparative embryological analysis has shown a similarity in the main of process of embryo differentiation produced under clinorotation and in the stationary control. At the early stages of embryogenesis, the distortion in suspensor formation was observed more frequently. Embryos generated in clinorotation variant had a wider range of developmental stages in comparison with the stationary control. At the stage of embryo maturation the various deviations in embryo differentiation were revealed. These distortions were connected both with cotyledon and radicle development. Possible reasons for deviations in the process of embryogenesis in condition of altered gravity are discussed.

Popova, A.; Ivanenko, G.

354

Real-time Embryogenesis in Live Caenorhabditis elegans Worms  

NSDL National Science Digital Library

This is a lab exercise geared toward first-year undergraduate biology majors, where they get to view early embryogenesis in a live animal. In this exercise students will prepare slides if live C. elegans embryos, find one- or two-cell stage embryos, and observe cleavage stage of embryogenesis over the course of 30 minutes.

Dr. Anita G Fernandez (Fairfield University Biology)

2011-11-21

355

SOMATIC CROSSING OVER IN GLYCINE MAX (L.) MERRILL: EFFECT OF SOME INHIBITORS OF DNA SYNTHESIS ON THE INDUCTION OF SOMATIC CROSSING OVER AND POINT MUTATIONS  

Microsoft Academic Search

Glycine max (soybean) is the only known higher plant with a definitely established occurrence of somatic crossing over. This material lends itself to the analysis of somatic crossing over, gross chromosomal aberrations and mu- tations, all of which may be induced by the same treatment of the mutagen given to seeds. This is made possible because gene Y,, for chlorophyll

B. K. VIG

1973-01-01

356

Somatic complaints in frontotemporal dementia.  

PubMed

Frontotemporal dementia (FTD) is associated with a broad spectrum of clinical characteristics. The objective of this study was to analyze the prevalence of unexplained somatic complaints in neuropathologically verified FTD. We also examined whether the somatic presentations correlated with protein pathology or regional brain pathology and if the patients with these somatic features showed more depressive traits. Ninety-seven consecutively neuropathologically verified FTLD patients were selected. All 97 patients were part of a longitudinal study of FTD and all medical records were systematically reviewed. The somatic complaints focused on were headache, musculoskeletal, gastro/urogenital and abnormal pain response. Symptoms of somatic character (either somatic complaints and/or abnormal pain response) were found in 40.2%. These patients did not differ from the total group with regard to gender, age at onset or duration. Six patients showed exaggerated reactions to sensory stimuli, whereas three patients showed reduced response to pain. Depressive traits were present in 38% and did not correlate with somatic complaints. Suicidal behavior was present in 17 patients, in 10 of these suicidal behavior was concurrent with somatic complaints. No clear correlation between somatic complaints and brain protein pathology, regional pathology or asymmetric hemispherical atrophy was found. Our results show that many FTD patients suffer from unexplained somatic complaints before and/or during dementia where no clear correlation can be found with protein pathology or regional degeneration. Somatic complaints are not covered by current diagnostic criteria for FTD, but need to be considered in diagnostics and care. The need for prospective studies with neuropathological follow up must be stressed as these phenomena remain unexplained, misinterpreted, bizarre and, in many cases, excruciating. PMID:25232513

Landqvist Waldö, Maria; Santillo, Alexander Frizell; Gustafson, Lars; Englund, Elisabet; Passant, Ulla

2014-01-01

357

Somatic complaints in frontotemporal dementia  

PubMed Central

Frontotemporal dementia (FTD) is associated with a broad spectrum of clinical characteristics. The objective of this study was to analyze the prevalence of unexplained somatic complaints in neuropathologically verified FTD. We also examined whether the somatic presentations correlated with protein pathology or regional brain pathology and if the patients with these somatic features showed more depressive traits. Ninety-seven consecutively neuropathologically verified FTLD patients were selected. All 97 patients were part of a longitudinal study of FTD and all medical records were systematically reviewed. The somatic complaints focused on were headache, musculoskeletal, gastro/urogenital and abnormal pain response. Symptoms of somatic character (either somatic complaints and/or abnormal pain response) were found in 40.2%. These patients did not differ from the total group with regard to gender, age at onset or duration. Six patients showed exaggerated reactions to sensory stimuli, whereas three patients showed reduced response to pain. Depressive traits were present in 38% and did not correlate with somatic complaints. Suicidal behavior was present in 17 patients, in 10 of these suicidal behavior was concurrent with somatic complaints. No clear correlation between somatic complaints and brain protein pathology, regional pathology or asymmetric hemispherical atrophy was found. Our results show that many FTD patients suffer from unexplained somatic complaints before and/or during dementia where no clear correlation can be found with protein pathology or regional degeneration. Somatic complaints are not covered by current diagnostic criteria for FTD, but need to be considered in diagnostics and care. The need for prospective studies with neuropathological follow up must be stressed as these phenomena remain unexplained, misinterpreted, bizarre and, in many cases, excruciating. PMID:25232513

Landqvist Waldö, Maria; Santillo, Alexander Frizell; Gustafson, Lars; Englund, Elisabet; Passant, Ulla

2014-01-01

358

Intravenous somatic gene transfer with antisense tissue factor restores blood flow by reducing tumor necrosis factor-induced tissue factor expression and fibrin deposition in mouse meth-A sarcoma.  

PubMed Central

Fibrin is deposited on the endothelial cell surface in the vasculature of murine methylcholanthrene A-induced sarcomas after injection of tumor necrosis factor (TNF). Capillary endothelial cells of the tumor vascular bed become positive for tissue factor after TNF injection, based on immunocytochemistry and in situ hybridization. Intravascular clot formation was not dependent on tissue factor derived from tumor cells, since in vessels of tumors not expressing tissue factor, TNF also induced fibrin/fibrinogen deposition. However, the time course of fibrin/fibrinogen deposition after TNF differed in tumors expressing no, little, or greater amounts of tissue factor. Fibrin/fibrinogen deposition was more rapid in tumors in which the neoplastic cells expressed tissue factor than in tumors not expressing tissue factor. In the tumors not expressing tissue factor, activation of coagulation was dependent on TNF-induced synthesis of tissue factor by host cells, i.e., endothelium or monocytes/macrophages. Intravenous somatic gene transfer with tissue factor cDNA in the antisense orientation (but not sense or vector alone) reduced intravascular fibrin/fibrinogen deposition and restored blood flow to the tumor, showing that de novo tissue factor expression is central in TNF-induced activation of the coagulation mechanism. PMID:8636400

Zhang, Y.; Deng, Y.; Wendt, T.; Liliensiek, B.; Bierhaus, A.; Greten, J.; He, W.; Chen, B.; Hach-Wunderle, V.; Waldherr, R.; Ziegler, R.; Männel, D.; Stern, D. M.; Nawroth, P. P.

1996-01-01

359

Histology of Organogenic and Embryogenic Responses in Cotyledons of Somatic Embryos of Quercus Suber L.  

PubMed

In cork oak (Quercus suber L.), recurrent embryogenesis is produced in vitro through autoembryony without exogenous plant growth regulators (PGRs); secondary embryos appear on the embryo axis but seldom on cotyledons. Focusing mainly on the histological origin of neoformations, we investigated the influence of the embryo axis and exogenous PGRs on the embryogenic potential of somatic embryo cotyledons. Isolated cotyledons of somatic embryos became necrotic when cultured on PGR-free medium but gave secondary embryos when cultured on media containing benzyladenine and naphthaleneacetic acid. Cotyledons of cork oak somatic embryos are competent to give embryogenic responses. Isolated cotyledons without a petiole showed a lower percentage of embryogenic response than did those with a petiole. In petioles, somatic embryos arose from inner parenchyma tissues following a multicellular budding pattern. Joined to the embryo axis, cotyledons did not show morphogenic responses when cultured on PGR-free medium but revealed budlike and phylloid formations when cultured on medium with PGRs. The different morphogenic behavior displayed by somatic cotyledons indicates an influence of the embryo axis and indicates a relationship between organogenic and embryogenic regeneration pathways. PMID:10817970

Puigderrajols; Celestino; Suils; Toribio; Molinas

2000-05-01

360

Embryogenesis: Pattern Formation from a Single Cell  

PubMed Central

During embryogenesis a single cell gives rise to a functional multicellular organism. In higher plants, as in many other multicellular systems, essential architectural features, such as body axes and major tissue layers are established early in embryogenesis and serve as a positional framework for subsequent pattern elaboration. In Arabidopsis, the apicalbasal axis and the radial pattern of tissues wrapped around it are already recognizable in young embryos of only about a hundred cells in size. This early axial pattern seems to provide a coordinate system for the embryonic initiation of shoot and root. Findings from genetic studies in Arabidopsis are revealing molecular mechanisms underlying the initial establishment of the axial core pattern and its subsequent elaboration into functional shoots and roots. The genetic programs operating in the early embryo organize functional cell patterns rapidly and reproducibly from minimal cell numbers. Understanding their molecular details could therefore greatly expand our ability to generate plant body patterns de novo, with important implications for plant breeding and biotechnology. PMID:22303250

Capron, Arnaud; Chatfield, Steven; Provart, Nicholas; Berleth, Thomas

2009-01-01

361

Hormonal responses during early embryogenesis in maize.  

PubMed

Plant hormones have been shown to regulate key processes during embryogenesis in the model plant Arabidopsis thaliana, but the mechanisms that determine the peculiar embryo pattern formation of monocots are largely unknown. Using the auxin and cytokinin response markers DR5 and TCSv2 (two-component system, cytokinin-responsive promoter version #2), as well as the auxin efflux carrier protein PIN1a (PINFORMED1a), we have studied the hormonal response during early embryogenesis (zygote towards transition stage) in the model and crop plant maize. Compared with the hormonal response in Arabidopsis, we found that detectable hormone activities inside the developing maize embryo appeared much later. Our observations indicate further an important role of auxin, PIN1a and cytokinin in endosperm formation shortly after fertilization. Apparent auxin signals within adaxial endosperm cells and cytokinin responses in the basal endosperm transfer layer as well as chalazal endosperm are characteristic for early seed development in maize. Moreover, auxin signalling in endosperm cells is likely to be involved in exogenous embryo patterning as auxin responses in the endosperm located around the embryo proper correlate with adaxial embryo differentiation and outgrowth. Overall, the comparison between Arabidopsis and maize hormone response and flux suggests intriguing mechanisms in monocots that are used to direct their embryo patterning, which is significantly different from that of eudicots. PMID:24646239

Chen, Junyi; Lausser, Andreas; Dresselhaus, Thomas

2014-04-01

362

Late Embryogenesis Abundant (LEA) proteins in legumes  

PubMed Central

Plants are exposed to different external conditions that affect growth, development, and productivity. Water deficit is one of these adverse conditions caused by drought, salinity, and extreme temperatures. Plants have developed different responses to prevent, ameliorate or repair the damage inflicted by these stressful environments. One of these responses is the activation of a set of genes encoding a group of hydrophilic proteins that typically accumulate to high levels during seed dehydration, at the last stage of embryogenesis, hence named Late Embryogenesis Abundant (LEA) proteins. LEA proteins also accumulate in response to water limitation in vegetative tissues, and have been classified in seven groups based on their amino acid sequence similarity and on the presence of distinctive conserved motifs. These proteins are widely distributed in the plant kingdom, from ferns to angiosperms, suggesting a relevant role in the plant response to this unfavorable environmental condition. In this review, we analyzed the LEA proteins from those legumes whose complete genomes have been sequenced such as Phaseolus vulgaris, Glycine max, Medicago truncatula, Lotus japonicus, Cajanus cajan, and Cicer arietinum. Considering their distinctive motifs, LEA proteins from the different groups were identified, and their sequence analysis allowed the recognition of novel legume specific motifs. Moreover, we compile their transcript accumulation patterns based on publicly available data. In spite of the limited information on these proteins in legumes, the analysis and data compiled here confirm the high correlation between their accumulation and water deficit, reinforcing their functional relevance under this detrimental conditions. PMID:23805145

Battaglia, Marina; Covarrubias, Alejandra A.

2013-01-01

363

Somatic diversification of antibody responses  

Microsoft Academic Search

Conclusions During the last decade, a substantial body of knowledge has been obtained on the generation of somatic diversification of the B cell repertoire, especially with regard to differentiation and selection of B cells in specialized microenvironments such as GCs and GALTs which are similar to each other morphologically and physiologically. Although the mechanisms for somatic diversification remain unclear, with

Biao Zheng; Garnett Kelsoe; Shuhua Han

1996-01-01

364

Histodifferentiation of somatic embryos in cotyledons of pineapple guava ( Feijoa sellowiana Berg)  

Microsoft Academic Search

Summary Somatic embryos of pineapple guava (Feijoa sellowiana Berg, Myrtaceae) were induced particularly well from the adaxial face of the cotyledons of zygotic embryos cultured on MS medium containing 1.0 mg\\/l 2,4-D and 0.3 M sucrose. Somatic embryos were never obtained from globular and heart-shaped zygotic embryos and embryos at the torpedo stage produced somatic embryos at lower frequencies than

J. M. Canhoto; G. S. Cruz

1996-01-01

365

Oak somatic and gametic embryos maturation is affected by charcoal and specific aminoacids mixture  

Microsoft Academic Search

– \\u000a \\u000a • Development of both somatic and gametic embryogenesis has many applications in clonal forestry and genetic improvement,\\u000a for instance as mass-propagation of genetically improved plants and production of pure lines through doubled-haploid plant\\u000a regeneration from gametic embryos.\\u000a \\u000a \\u000a \\u000a \\u000a – \\u000a \\u000a • The goal of this work was to improve growth, maturation and plantlet regeneration of cork oak (Quercus suber L.) embryos

Beatriz Pintos; Jose A. Manzanera; M. Angeles Bueno

2010-01-01

366

Somatic embryo-like structures of strawberry regenerated in vitro on media supplemented with 2,4-D and BAP.  

PubMed

Somatic embryo-like structures (SELS) were produced in vitro from leaf disk and petiole explants of two cultivars of strawberry (Fragaria x ananassa Duch) on Murashige and Skoog medium with different concentrations and combinations of 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (BAP) and sucrose to check the embryonic nature of these structures histologically. A large number of SELS could be regenerated in both cultivars on media with 2-4 mg L(-1) 2,4-D in combination with 0.5 -1 mg L(-1) BAP and 50 g x L(-1) sucrose. Histological examination of SELS revealed the absence of a root pole. Therefore these structures cannot be strictly classified as somatic embryos. The SELS formed under the tested culture conditions represent malformed shoot-like and leaf-like structures. The importance of these results for the propagation of strawberries via somatic embryogenesis is discussed. PMID:24377134

Omar, Genesia F; Mohamed, Fouad H; Haensch, Klaus-Thomas; Sarg, Sawsan H; Morsey, Mohamed M

2013-09-01

367

High genetic and epigenetic stability in Coffea arabica plants derived from embryogenic suspensions and secondary embryogenesis as revealed by AFLP, MSAP and the phenotypic variation rate.  

PubMed

Embryogenic suspensions that involve extensive cell division are risky in respect to genome and epigenome instability. Elevated frequencies of somaclonal variation in embryogenic suspension-derived plants were reported in many species, including coffee. This problem could be overcome by using culture conditions that allow moderate cell proliferation. In view of true-to-type large-scale propagation of C. arabica hybrids, suspension protocols based on low 2,4-D concentrations and short proliferation periods were developed. As mechanisms leading to somaclonal variation are often complex, the phenotypic, genetic and epigenetic changes were jointly assessed so as to accurately evaluate the conformity of suspension-derived plants. The effects of embryogenic suspensions and secondary embryogenesis, used as proliferation systems, on the genetic conformity of somatic embryogenesis-derived plants (emblings) were assessed in two hybrids. When applied over a 6 month period, both systems ensured very low somaclonal variation rates, as observed through massive phenotypic observations in field plots (0.74% from 200,000 plant). Molecular AFLP and MSAP analyses performed on 145 three year-old emblings showed that polymorphism between mother plants and emblings was extremely low, i.e. ranges of 0-0.003% and 0.07-0.18% respectively, with no significant difference between the proliferation systems for the two hybrids. No embling was found to cumulate more than three methylation polymorphisms. No relation was established between the variant phenotype (27 variants studied) and a particular MSAP pattern. Chromosome counting showed that 7 of the 11 variant emblings analyzed were characterized by the loss of 1-3 chromosomes. This work showed that both embryogenic suspensions and secondary embryogenesis are reliable for true-to-type propagation of elite material. Molecular analyses revealed that genetic and epigenetic alterations are particularly limited during coffee somatic embryogenesis. The main change in most of the rare phenotypic variants was aneuploidy, indicating that mitotic aberrations play a major role in somaclonal variation in coffee. PMID:23418563

Bobadilla Landey, Roberto; Cenci, Alberto; Georget, Frédéric; Bertrand, Benoît; Camayo, Gloria; Dechamp, Eveline; Herrera, Juan Carlos; Santoni, Sylvain; Lashermes, Philippe; Simpson, June; Etienne, Hervé

2013-01-01

368

The effects of microgravity on gametogenesis, fertilization, and early embryogenesis  

NASA Astrophysics Data System (ADS)

Gametogenesis fertilization and early embryogenesis are crucial periods for normal development afterwards In past three decades many experiments have been conducted in space and in simulated weightlessness induced by clinostats to elucidate the issue Different animal species including Drosophila wasp shrimp fish amphibian mouse rats etc have been used for the study Oogenesis and spermatogenesis are affected by microgravity in different ways Some researches found that microgravity condition perturbed the process of oogenesis in many species A significant increased frequency of chromosomal non-disjunction was found in Drosophila females resulting the loss of chromosomes during meiosis and inhibition of cell division Studies on wasp showed a decreased hatchability and accumulation of unhatched eggs when the insects were exposed to spaceflight at different stages of oogenesis For experiments conducted on vertebrate animal models the results are somehow different however Microgravity has no significant effect for fish Medaka etc amphibian South African clawed toad Xenopus laevis or mammals mouse Spermatogenesis on the other hand is more significantly affected by microgravity condition Some researches indicated sperm are sensitive to changes in gravitational force and this sensitivity affects the ability of sperm to fertilize eggs Sperm swim with higher velocity in microgravity which is coupled with altered protein phosphorylation level in sperm under microgravity condition Microgravity also induced activation of the

Tan, X.

369

Ophiobolin A from Bipolaris oryzae Perturbs Motility and Membrane Integrities of Porcine Sperm and Induces Cell Death on Mammalian Somatic Cell Lines  

PubMed Central

Bipolaris oryzae is a phytopathogenic fungus causing a brown spot disease in rice, and produces substance that strongly perturbs motility and membrane integrities of boar spermatozoa. The substance was isolated from the liquid culture of the fungal strain using extraction and a multi-step semi-preparative HPLC procedures. Based on the results of mass spectrometric and 2D NMR techniques, the bioactive molecule was identified as ophiobolin A, a previously described sesterterpene-type compound. The purified ophiobolin A exhibited strong motility inhibition and viability reduction on boar spermatozoa. Furthermore, it damaged the sperm mitochondria significantly at sublethal concentration by the dissipation of transmembrane potential in the mitochondrial inner membrane, while the plasma membrane permeability barrier remained intact. The study demonstrated that the cytotoxicity of ophiobolin A toward somatic cell lines is higher by 1–2 orders of magnitude compared to other mitochondriotoxic mycotoxins, and towards sperm cells unique by replacing the progressive motility by shivering tail beating at low exposure concentration. PMID:25251540

Bencsik, Ottó; Papp, Tamás; Berta, Máté; Zana, Annamária; Forgó, Péter; Dombi, György; Andersson, Maria A.; Salkinoja-Salonen, Mirja; Vágvölgyi, Csaba; Szekeres, András

2014-01-01

370

Expression of developmental genes during early embryogenesis of Hydra.  

PubMed

Hydra is a classical model to study key features of embryogenesis such as axial patterning and stem cell differentiation. In contrast to other organisms where these mechanisms are active only during embryonic development, in Hydra they can be studied in adults. The underlying assumption is that the machinery governing adult patterning mimics regulatory mechanisms which are also active during early embryogenesis. Whether, however, Hydra embryogenesis is governed by the same mechanisms which are controlling adult patterning, remains to be shown. In this paper, in precisely staged Hydra embryos, we examined the expression pattern of 15 regulatory genes shown previously to play a role in adult patterning and cell differentiation. RT-PCR revealed that most of the genes examined were expressed in rather late embryonic stages. In situ hybridization, nuclear run-on experiments, and staining of nucleolar organizer region-associated proteins indicated that genes expressed in early embryos are transcribed in the engulfed "nurse cells" (endocytes). This is the first direct evidence that endocytes in Hydra not only provide nutrients to the developing oocyte but also produce maternal factors critical for embryogenesis. Our findings are an initial step towards understanding the molecular machinery controlling embryogenesis of a key group of basal metazoans and raise the possibility that in Hydra there are differences in the mechanisms controlling embryogenesis and adult patterning. PMID:12883882

Fröbius, Andreas C; Genikhovich, Gregory; Kürn, Ulrich; Anton-Erxleben, Friederike; Bosch, Thomas C G

2003-09-01

371

ER71 directs mesodermal fate decisions during embryogenesis.  

PubMed

Er71 mutant embryos are nonviable and lack hematopoietic and endothelial lineages. To further define the functional role for ER71 in cell lineage decisions, we generated genetically modified mouse models. We engineered an Er71-EYFP transgenic mouse model by fusing the 3.9 kb Er71 promoter to the EYFP reporter gene. Using FACS and transcriptional profiling, we examined the EYFP(+) population of cells in Er71 mutant and wild-type littermates. In the absence of ER71, we observed an increase in the number of EYFP-expressing cells, increased expression of the cardiac molecular program and decreased expression of the hemato-endothelial program, as compared with wild-type littermate controls. We also generated a novel Er71-Cre transgenic mouse model using the same 3.9 kb Er71 promoter. Genetic fate-mapping studies revealed that the ER71-expressing cells give rise to the hematopoietic and endothelial lineages in the wild-type background. In the absence of ER71, these cell populations contributed to alternative mesodermal lineages, including the cardiac lineage. To extend these analyses, we used an inducible embryonic stem/embryoid body system and observed that ER71 overexpression repressed cardiogenesis. Together, these studies identify ER71 as a critical regulator of mesodermal fate decisions that acts to specify the hematopoietic and endothelial lineages at the expense of cardiac lineages. This enhances our understanding of the mechanisms that govern mesodermal fate decisions early during embryogenesis. PMID:21989919

Rasmussen, Tara L; Kweon, Junghun; Diekmann, Mackenzie A; Belema-Bedada, Fikru; Song, Qingfeng; Bowlin, Kathy; Shi, Xiaozhong; Ferdous, Anwarul; Li, Tongbin; Kyba, Michael; Metzger, Joseph M; Koyano-Nakagawa, Naoko; Garry, Daniel J

2011-11-01

372

Characterization of conservative somatic instability of the CAG repeat region in Huntington`s disease  

SciTech Connect

Instability and enlargement of a CAG repeat region at the beginning of the huntingtin gene (IT-15) has been linked with Huntington`s disease. The CAG repeat size shows a highly significant correlation with age-of-onset of clinicial features in individuals with 40 or more repeats who have Huntington disease. The clinical status of nonsymptomatic individuals with 30 to 39 CAG repeats is considered ambiguous. In order to define more carefully the nature of the HD expansion instability, we examined patients in our HD population using a discriminating fluorescence-based PCR approach. The degree of somatic mutation increases with both earlier age of onset and the size of the inherited allele. A single prominent band one repeat larger than the index peak was typical in individuals with 40-41 CAG repeats. Three to four larger bands are typically discerned in individuals with 50 or more repeats. In an extreme example, an individual with approximately 95 repeats had at least 8 prominent bands. Plotting the degree of somatic mutation relative to the size of the HD allele shows somatic mutation activity increases with size. By this approach 40-60% of the alleles in a 40-41 CAG repeat HD loci is represented in the primary allele. In contrast, the primary allele represents a relatively minor proportion of the total alleles for expansions greater than 50 CAG repeats (10-20%). The limited range of somatic mutation suggest that the instability is restricted to very early stages of embryogenesis before tissue development diverges or that persistent somatic instability occurs at a slow rate. Therefore, the properties of somatic instability in Huntington`s disease have aspects that are both in common but also different from that found in other trinucleotide repeat expanding diseases such as myotonic muscular dystrophy and fragile X syndrome.

Schaefer, F.V.; Calikoglu, A.S.; Whetsell, L.H. [H.A. Chapman Research Institute of Medical Genetics, Tulsa, OK (United States)

1994-09-01

373

Somatization and somatic symptom presentation in cancer: a neglected area.  

PubMed

Abstract The recognition of somatization process in cancer patients is a challenging and neglected area, for the extreme difficulty in differentiating and assessing the psycho(patho)logical components from those biologically determined and related to cancer and cancer treatment, as well as for the scarce usefulness of rigid categorical DSM criteria. However, several dimensions of somatization (and the interconnected concept of abnormal illness behaviour) have been shown to be diagnosable in cancer patients and to negatively influence coping and quality of life outcomes. An integration of the formal DSM-ICD nosology with a system specifically taking into account the patients' emotional responses to cancer and cancer treatment, such as the Diagnostic Criteria for Psychosomatic Research (DCPR), is suggested. More data on some specific symptom dimensions, including pain, fatigue and sexual disorders, are needed to examine their possible psychological components. More research is also needed regarding the association of somatization with personality traits (e.g. type D distressed personality, alexithymia), developmental dimensions (e.g. attachment), and cultural issues (e.g. culturally mediated attributional styles to somatic symptoms). Also, the impact and effectiveness of specific therapeutic intervention in 'somatizing' cancer patients is necessary. PMID:23383666

Grassi, Luigi; Caruso, Rosangela; Nanni, Maria Giulia

2013-02-01

374

Embryonic and somatic cell cloning.  

PubMed

Revolutionary opportunities in biology, medicine and agriculture arise from the observation that offspring are obtained after nuclear transfer if somatic donor cells are induced to become quiescent. Exploitation of many of these opportunities will depend upon optimizing procedures for nuclear transfer. This may come about through an understanding of the means by which factors in the oocyte cytoplasm act upon the DNA of the transferred nucleus to regulate gene expression. Similarly, research will extend the procedure to other species. This technology may be used for embryo production, the introduction of genetic change and the derivation of cells needed to treat human diseases. Groups of genetically identical animals will be used in research to control genetic variation and to allow transfer of cells between individuals. In agriculture, production of a small number of clones will separate genetic and environmental effects, whereas production of larger numbers of offspring will disseminate genetic improvement from nucleus herds. Precise genetic modification will be achieved by site specific recombination in the donor cells before nuclear transfer. In all mammals it will become possible to define the role of any gene product and to analyse the mechanisms that regulate gene expression. Medical uses of these techniques will include the production of proteins needed to treat disease and the supply of organs such as hearts, livers and kidneys from pigs. As genome mapping projects identify loci associated with traits of commercial importance in agriculture then gene targeting will be used to study this effect. Finally, cells capable of differentiation into any of the tissues of a patient will provide treatment for diseases reflecting damage to a specific cell population that neither repairs nor replaces itself. PMID:10612470

Wilmut, I; Young, L; Campbell, K H

1998-01-01

375

A Novel Mouse Model for the Hyper-IgM Syndrome: A Spontaneous Activation-Induced Cytidine Deaminase Mutation Leading to Complete Loss of Ig Class Switching and Reduced Somatic Hypermutation  

PubMed Central

We describe a spontaneously derived mouse line that completely failed to induce Ig class switching in vitro and in vivo. The mice inherited abolished IgG serum titers in a recessive manner caused by a spontaneous G?A transition mutation in codon 112 of the aicda gene, leading to an arginine to histidine replacement (AIDR112H). Ig class switching was completely reconstituted by expressing wild-type AID. Mice homozygous for AIDR112H had peripheral B cell hyperplasia and large germinal centers in the absence of Ag challenge. Immunization with SRBCs elicited an Ag-specific IgG1 response in wild-type mice, whereas AIDR112H mice failed to produce IgG1 and had reduced somatic hypermutation. The phenotype recapitulates the human hyper-IgM (HIGM) syndrome that is caused by point mutations in the orthologous gene in humans, and the AIDR112H mutation is frequently found in HIGM patients. The AIDR112H mouse model for HIGM provides a powerful and more precise tool than conventional knockout strategies. PMID:25252954

Dahlberg, Carin I. M.; He, Minghui; Visnes, Torkild; Torres, Magda Liz; Cortizas, Elena M.; Verdun, Ramiro E.; Ström, Lena

2014-01-01

376

Chromatin Changes in Reprogramming of Mammalian Somatic Cells  

PubMed Central

Abstract Somatic cell nuclear transfer (SCNT), cell fusion, and induced pluripotent stem cells (iPSCs) technologies are three strategies that allow reprogramming somatic cells into the pluripotent state; however, the efficiency is low and the mechanisms are not fully clear. In addition, there are reports that changes in chromatin play a critical role in these reprogramming strategies by modulating binding of transcription factors to their targets. In this review, we mainly discuss inactivation of the X chromosome, chromatin decondensation and remodeling, histone modifications, and histone variants in the three strategies. This review will provide an insight for future nuclear reprogramming research. PMID:23987213

Xu, Rong; Zhang, Shiqiang

2014-01-01

377

Metabolome Analysis of Drosophila melanogaster during Embryogenesis  

PubMed Central

The Drosophila melanogaster embryo has been widely utilized as a model for genetics and developmental biology due to its small size, short generation time, and large brood size. Information on embryonic metabolism during developmental progression is important for further understanding the mechanisms of Drosophila embryogenesis. Therefore, the aim of this study is to assess the changes in embryos’ metabolome that occur at different stages of the Drosophila embryonic development. Time course samples of Drosophila embryos were subjected to GC/MS-based metabolome analysis for profiling of low molecular weight hydrophilic metabolites, including sugars, amino acids, and organic acids. The results showed that the metabolic profiles of Drosophila embryo varied during the course of development and there was a strong correlation between the metabolome and different embryonic stages. Using the metabolome information, we were able to establish a prediction model for developmental stages of embryos starting from their high-resolution quantitative metabolite composition. Among the important metabolites revealed from our model, we suggest that different amino acids appear to play distinct roles in different developmental stages and an appropriate balance in trehalose-glucose ratio is crucial to supply the carbohydrate source for the development of Drosophila embryo. PMID:25121768

An, Phan Nguyen Thuy; Yamaguchi, Masamitsu; Bamba, Takeshi; Fukusaki, Eiichiro

2014-01-01

378

Acrolein and embryogenesis: an experimental study  

SciTech Connect

The effects of acrolein were studied on the chick embryos of 48 and 72 hr of incubation. Acrolein was dissolved in physiological saline and injected into the air sacs of the eggs at doses ranging from 0.001 to 0.1 mg per egg. The controls received and equal amount of saline only (0.1 ml per egg). All the embryos including controls were examined at Day 13. In all, 600 eggs were utilized for this investigation. At 48 hr incubation, the percentage survival ranged from 80 to 0 as the dosage of acrolein was increased. Embryonic mortality following 72 hr incubation did not increase significantly at any dose level. Gross malformations such as short and twisted limbs, everted viscera, microphthalmia, short and twisted neck, and hemorrhage over the body were observed. The frequency and the types of gross abnormalities did not vary much in the 48- or 72-hr-treated groups. The incidence of malformation in the controls was low. The results of this study indicates that acrolein is embryotoxic at higher doses and moderately teratogenic to chick embryogenesis.

Chhibber, G.; Cilani, S.H.

1986-01-01

379

Environmental magnetic fields: Influences on early embryogenesis  

SciTech Connect

A 10-mG, 50 to 60-Hz magnetic field is in the intensity and frequency range that people worldwide are often exposed to in homes and in the workplace. Studies about the effects of 50- to 100-Hz electromagnetic fields on various species of animal embryos (fish, chick, fly, sea urchin, rat, and mouse) indicate that early stages of embryonic development are responsive to fluctuating magnetic fields. Chick, sea urchin, and mouse embryos are responsive to magnetic field intensities of 10-100 mG. Results from studies on sea urchin embryos indicate that exposure to conditions of rotating 60-Hz magnetic fields, e.g., similar to those in our environment, interferes with cell proliferation at the morula stage in a manner dependent on field intensity. The cleavage stages, prior to the 64-cell stage, were not delayed by this rotating 60-Hz magnetic field suggesting that the ionic surges, DNA replication, and translational events essential for early cleavage stages were not significantly altered. Studies of histone synthesis in early sea urchin embryos indicated that the rotating 60-Hz magnetic field decreased zygotic expression of early histone genes at the morula stage and suggests that this decrease in early histone production was limiting to cell proliferation. Whether these comparative observations from animal development studies will be paralleled by results from studies of human embryogenesis, as suggested by some epidemiology studies, has yet to be established. 38 refs.

Cameron, I.L.; Hardman, W.E.; Winters, W.D.; Zimmerman, S.; Zimmerman, A.M. (Univ. of Texas Health Science Center, San Antonio (United States))

1993-04-01

380

Drosophila Embryogenesis Scales Uniformly across Temperature in Developmentally Diverse Species  

PubMed Central

Temperature affects both the timing and outcome of animal development, but the detailed effects of temperature on the progress of early development have been poorly characterized. To determine the impact of temperature on the order and timing of events during Drosophila melanogaster embryogenesis, we used time-lapse imaging to track the progress of embryos from shortly after egg laying through hatching at seven precisely maintained temperatures between 17.5°C and 32.5°C. We employed a combination of automated and manual annotation to determine when 36 milestones occurred in each embryo. D. melanogaster embryogenesis takes 33 hours at 17.5°C, and accelerates with increasing temperature to a low of 16 hours at 27.5°C, above which embryogenesis slows slightly. Remarkably, while the total time of embryogenesis varies over two fold, the relative timing of events from cellularization through hatching is constant across temperatures. To further explore the relationship between temperature and embryogenesis, we expanded our analysis to cover ten additional Drosophila species of varying climatic origins. Six of these species, like D. melanogaster, are of tropical origin, and embryogenesis time at different temperatures was similar for them all. D. mojavensis, a sub-tropical fly, develops slower than the tropical species at lower temperatures, while D. virilis, a temperate fly, exhibits slower development at all temperatures. The alpine sister species D. persimilis and D. pseudoobscura develop as rapidly as tropical flies at cooler temperatures, but exhibit diminished acceleration above 22.5°C and have drastically slowed development by 30°C. Despite ranging from 13 hours for D. erecta at 30°C to 46 hours for D. virilis at 17.5°C, the relative timing of events from cellularization through hatching is constant across all species and temperatures examined here, suggesting the existence of a previously unrecognized timer controlling the progress of embryogenesis that has been tuned by natural selection as each species diverges. PMID:24762628

Kuntz, Steven G.; Eisen, Michael B.

2014-01-01

381

Changes in pectins and MAPKs related to cell development during early microspore embryogenesis in Quercus suber L.  

PubMed

The occurrence and significance of changes in cell wall components and signalling molecules has been investigated during early microspore embryogenesis in cork oak (Quercus suber L.) in relation to cell proliferation and cell differentiation. Microspore embryogenesis has been induced in in vitro anther cultures of Q. suber by the application of a stress treatment of 33 degrees C. After the treatment, microspores at the responsive developmental stage of vacuolate microspore switched towards proliferation and the embryogenesis pathway to further produce haploid plantlets. Ultrastructural and immunocytochemical analysis revealed changes in cell organisation after induction at different developmental stages, the cellular features displayed being in relation to the activation of proliferative activity and the beginning of differentiation in young and late proembryos. Immunogold labelling with JIM5 and JIM7 antibodies showed a different presence of pectin and level of its esterification in cell walls at different developmental stages. Non-esterified pectins were found in higher proportions in cells of late proembryos, suggesting that pectin de-esterification could be related to the beginning of differentiation. The presence and subcellular distribution of Erk 1/2 MAPK homologues have been investigated by immunoblotting, immunofluorescence and immunogold labelling. The results showed an increase in the expression of these proteins with a high presence in the nucleus, during early microspore proembryos development. The reported changes during early microspore embryogenesis are modulated in relation to proliferation and differentiation events. These findings provided new evidences for a role of MAPK signalling pathways in early microspore embryogenesis, specifically in proliferation, and would confer information for the cell fate and the direction of the cell development. PMID:15346811

Ramírez, Carmen; Testillano, Pilar S; Pintos, Beatriz; Moreno-Risueńo, Miguel A; Bueno, María A; Risueńo, María C

2004-07-01

382

Muscle formation during embryogenesis of the polychaete Ophryotrocha diadema (Dorvilleidae) – new insights into annelid muscle patterns  

PubMed Central

Background The standard textbook information that annelid musculature consists of oligochaete-like outer circular and inner longitudinal muscle-layers has recently been called into question by observations of a variety of complex muscle systems in numerous polychaete taxa. To clarify the ancestral muscle arrangement in this taxon, we compared myogenetic patterns during embryogenesis of Ophryotrocha diadema with available data on oligochaete and polychaete myogenesis. This work addresses the conflicting views on the ground pattern of annelids, and adds to our knowledge of the evolution of lophotrochozoan taxa. Results Somatic musculature in Ophryotrocha diadema can be classified into the trunk, prostomial/peristomial, and parapodial muscle complexes. The trunk muscles comprise strong bilateral pairs of distinct dorsal and ventral longitudinal strands. The latter are the first to differentiate during myogenesis. They originate within the peristomium and grow posteriorly through the continuous addition of myocytes. Later, the longitudinal muscles also expand anteriorly and form a complex arrangement of prostomial muscles. Four embryonic parapodia differentiate in an anterior-to-posterior progression, significantly contributing to the somatic musculature. Several diagonal and transverse muscles are present dorsally. Some of the latter are situated external to the longitudinal muscles, which implies they are homologous to the circular muscles of oligochaetes. These circular fibers are only weakly developed, and do not appear to form complete muscle circles. Conclusion Comparison of embryonic muscle patterns showed distinct similarities between myogenetic processes in Ophryotrocha diadema and those of oligochaete species, which allows us to relate the diverse adult muscle arrangements of these annelid taxa to each other. These findings provide significant clues for the interpretation of evolutionary changes in annelid musculature. PMID:18171469

Bergter, Annette; Brubacher, John L; Paululat, Achim

2008-01-01

383

Differential regulation of DNA damage response activation between somatic and germline cells in Caenorhabditis elegans  

PubMed Central

The germline of Caenorhabditis elegans is a well-established model for DNA damage response (DDR) studies. However, the molecular basis of the observed cell death resistance in the soma of these animals remains unknown. We established a set of techniques to study ionizing radiation-induced DNA damage generation and DDR activation in a whole intact worm. Our single-cell analyses reveal that, although germline and somatic cells show similar levels of inflicted DNA damage, somatic cells, differently from germline cells, do not activate the crucial apical DDR kinase ataxia-telengiectasia mutated (ATM). We also show that DDR signaling proteins are undetectable in all somatic cells and this is due to transcriptional repression. However, DNA repair genes are expressed and somatic cells retain the ability to efficiently repair DNA damage. Finally, we demonstrate that germline cells, when induced to transdifferentiate into somatic cells within the gonad, lose the ability to activate ATM. Overall, these observations provide a molecular mechanism for the known, but hitherto unexplained, resistance to DNA damage-induced cell death in C. elegans somatic cells. We propose that the observed lack of signaling and cell death but retention of DNA repair functions in the soma is a Caenorhabditis-specific evolutionary-selected strategy to cope with its lack of adult somatic stem cell pools and regenerative capacity. PMID:22705849

Vermezovic, J; Stergiou, L; Hengartner, M O; d'Adda di Fagagna, F

2012-01-01

384

Histone variant macroH2A marks embryonic differentiation in vivo and acts as an epigenetic barrier to induced pluripotency  

PubMed Central

Summary How cell fate becomes restricted during somatic cell differentiation is a long-lasting question in biology. Epigenetic mechanisms not present in pluripotent cells and acquired during embryonic development are expected to stabilize the differentiated state of somatic cells and thereby restrict their ability to convert to another fate. The histone variant macroH2A acts as a component of an epigenetic multilayer that heritably maintains the silent X chromosome and has been shown to restrict tumor development. Here we show that macroH2A marks the differentiated cell state during mouse embryogenesis. MacroH2A.1 was found to be present at low levels upon the establishment of pluripotency in the inner cell mass and epiblast, but it was highly enriched in the trophectoderm and differentiated somatic cells later in mouse development. Chromatin immunoprecipitation revealed that macroH2A.1 is incorporated in the chromatin of regulatory regions of pluripotency genes in somatic cells such as mouse embryonic fibroblasts and adult neural stem cells, but not in embryonic stem cells. Removal of macroH2A.1, macroH2A.2 or both increased the efficiency of induced pluripotency up to 25-fold. The obtained induced pluripotent stem cells reactivated pluripotency genes, silenced retroviral transgenes and contributed to chimeras. In addition, overexpression of macroH2A isoforms prevented efficient reprogramming of epiblast stem cells to naďve pluripotency. In summary, our study identifies for the first time a link between an epigenetic mark and cell fate restriction during somatic cell differentiation, which helps to maintain cell identity and antagonizes induction of a pluripotent stem cell state. PMID:23077180

Pasque, Vincent; Radzisheuskaya, Aliaksandra; Gillich, Astrid; Halley-Stott, Richard P.; Panamarova, Maryna; Zernicka-Goetz, Magdalena; Surani, M. Azim; Silva, José C. R.

2012-01-01

385

Histone variant macroH2A marks embryonic differentiation in vivo and acts as an epigenetic barrier to induced pluripotency.  

PubMed

How cell fate becomes restricted during somatic cell differentiation is a long-lasting question in biology. Epigenetic mechanisms not present in pluripotent cells and acquired during embryonic development are expected to stabilize the differentiated state of somatic cells and thereby restrict their ability to convert to another fate. The histone variant macroH2A acts as a component of an epigenetic multilayer that heritably maintains the silent X chromosome and has been shown to restrict tumor development. Here we show that macroH2A marks the differentiated cell state during mouse embryogenesis. MacroH2A.1 was found to be present at low levels upon the establishment of pluripotency in the inner cell mass and epiblast, but it was highly enriched in the trophectoderm and differentiated somatic cells later in mouse development. Chromatin immunoprecipitation revealed that macroH2A.1 is incorporated in the chromatin of regulatory regions of pluripotency genes in somatic cells such as mouse embryonic fibroblasts and adult neural stem cells, but not in embryonic stem cells. Removal of macroH2A.1, macroH2A.2 or both increased the efficiency of induced pluripotency up to 25-fold. The obtained induced pluripotent stem cells reactivated pluripotency genes, silenced retroviral transgenes and contributed to chimeras. In addition, overexpression of macroH2A isoforms prevented efficient reprogramming of epiblast stem cells to naďve pluripotency. In summary, our study identifies for the first time a link between an epigenetic mark and cell fate restriction during somatic cell differentiation, which helps to maintain cell identity and antagonizes induction of a pluripotent stem cell state. PMID:23077180

Pasque, Vincent; Radzisheuskaya, Aliaksandra; Gillich, Astrid; Halley-Stott, Richard P; Panamarova, Maryna; Zernicka-Goetz, Magdalena; Surani, M Azim; Silva, José C R

2012-12-15

386

Zygotic and somatic embryo morphogenesis in Pinus pinaster: comparative histological and histochemical study.  

PubMed

We compared morphogenesis and accumulation of storage proteins and starch in Pinus pinaster Ait. zygotic embryos with those in somatic embryos grown with different carbohydrate sources. The maturation medium for somatic embryos included 80 microM abscisic acid (ABA), 9 g l(-1) gellam gum and either glucose, sucrose or maltose at 44, 88, 175 or 263 mM in the presence or absence of 6% (w/v) polyethylene glycol (PEG) 4000 MW. Maturation medium containing 44 or 88 mM of a carbohydrate source produced only one or no cotyledonary somatic embryos per 0.6 g fresh mass of culture. The addition of PEG to the basal maturation medium resulted in a low yield of cotyledonary somatic embryos that generally showed incomplete development and anatomical abnormalities such as large intercellular spaces and large vacuoles. High concentrations of maltose also induced large intercellular spaces in the somatic embryonic cells, and 263 mM sucrose produced fewer and less developed cotyledonary somatic embryos compared with 175 mM sucrose, indicating that the effect of carbohydrate source is partially osmotic. Zygotic embryos had a lower dry mass than somatic embryos at the same stage of development. Starch granules followed a similar accumulation pattern in zygotic and somatic embryos. A low starch content was found in cotyledonary zygotic embryos and in somatic embryos developed in the presence of 175 mM maltose or 263 mM glucose. In zygotic embryos and in PEG-treated somatic embryos, protein bodies appeared later and were smaller and fewer than in well-developed somatic embryos grown without PEG. We propose that storage protein concentration might be a marker of embryo quality. PMID:17267357

Tereso, Susana; Zoglauer, Kurt; Milhinhos, Ana; Miguel, Célia; Oliveira, M Margarida

2007-05-01

387

Mechanical Cues in the Early Embryogenesis of Caenorhabditis elegans  

PubMed Central

Biochemical signaling pathways in developmental processes have been extensively studied, yet the role of mechanical cues during embryogenesis is much less explored. Here we have used selective plane illumination microscopy in combination with a simple mechanical model to quantify and rationalize cell motion during early embryogenesis of the small nematode Caenorhabditis elegans. As a result, we find that cell organization in the embryo until gastrulation is well described by a purely mechanical model that predicts cells to assume positions in which they face the least repulsive interactions from other cells and the embryo’s egg shell. Our findings therefore suggest that mechanical interactions are key for a rapid and robust cellular arrangement during early embryogenesis of C. elegans. PMID:24138856

Fickentscher, Rolf; Struntz, Philipp; Weiss, Matthias

2013-01-01

388

Somatic Treatments for Mood Disorders  

Microsoft Academic Search

Somatic treatments for mood disorders represent a class of interventions available either as a stand-alone option, or in combination with psychopharmacology and\\/or psychotherapy. Here, we review the currently available techniques, including those already in clinical use and those still under research. Techniques are grouped into the following categories: (1) seizure therapies, including electroconvulsive therapy and magnetic seizure therapy, (2) noninvasive

Moacyr A Rosa; Sarah H Lisanby

2012-01-01

389

Anorexia, coprophagia and somatic outcome  

Microsoft Academic Search

Serious insufficiencies of ego structure and functions may originate from early traumata. The absence or the crushing of fantasies and generally the failure of the symbolic function may be responsible for delusional solutions or for behavioral and somatic outcomes. These ‘solutions’ can be understood as regressions to supposedly inadequate primitive narcissism. The traces and the consequences of the primary traumata

Savvas Savvopoulos

2006-01-01

390

Detection of somatic mosaicism in DMD using computer-assisted laser densitometry  

SciTech Connect

Approximately two-thirds of Duchenne muscular dystrophy (DMD) patients have a deletion in the dystrophin gene located at Xp21.1. Two PCR-based multiplex systems have been developed which detect 98% of deletions in affected males. Diagnosis of carrier females requires densitometry of PCR products following gel electrophoresis to calculate dosage of specific exons. We have developed a system in which fluorescently labelled PCR products are analysed using a GENESCANNER automated fragment analyser (ABI). Dosage is determined using computer-assisted laser densitometry (CALD). Recently, we diagnosed somatic mosaicism in the mother of an affected boy using this method. PCR analysis showed that the patient had a deletion that included exons 47-51 of his dystrophin gene. CALD analysis on the patient`s 36-year-old mother revealed a 29-34% reduction in the intensity of the bands corresponding to the deleted region of the gene rather than the 50% reduction normally seen in carrier females. A skin biopsy was obtain and monoclonal fibroblast colonies were tested by CALD for the deletion. Four of the twenty colonies screened were found to be deleted while the remaining colonies had two intact copies of the gene. We conclude that this patient is a somatic mosaic for DMD and that the mutation was the result of a post-zygotic event. This is the only case of somatic mosaicism detected among 800 women from 400 DMD families tested using CALD in our laboratory. At least one other case of possible somatic mosaicism has been reported but not confirmed. Germinal mosaicism is thought to occur in approximately 10% of mothers of sporadic DMD patients. Our findings indicate that somatic mosaicism is a much rarer condition among DMD carriers, thus suggesting that mitotic mutations in the dystrophin gene are more likely to occur later in embryogenesis after differentiation of the germline.

Sutherland, J.E.; Allingham-Hawkins, D.J.; MacKenzie, J. [Hospital for Sick Children, Toronto (Canada)] [and others

1994-09-01

391

Genotoxic effects of cisplatin in somatic tissue of Drosophila melanogaster  

SciTech Connect

Third instar larvae of Drosophila melanogaster transdihybrid for mwh and flr were exposed to varying concentrations of cisplatin by feeding on dry media wetted with aqueous solutions of the test compound. Larval feeding continued until pupation, and surviving transdihybrid adults were collected seven days following commencement of feeding. Wings of adults were removed and scored under 400X magnification for the presence of twin spots and single spots comprised of clones of cells possessing malformed wing hairs. Cisplatin was found to induce both twin spots and single spots, and significant linear concentration-response relationships were obtained with respect to the induction of all endpoints. This capacity to induce mitotic exchange in the somatic tissue of Drosophila compares well with the compound's reported ability to induce chromosome breaks in Drosophila germ cells. However, not all compounds possess similar genotoxic profiles in the somatic an germ tissue of Drosophila.

Katz, A.J.

1987-01-01

392

ERECTA family genes regulate development of cotyledons during embryogenesis.  

PubMed

Receptor-like kinases are important regulators of plant growth. Often a single receptor is involved in regulation of multiple developmental processes in a variety of tissues. ERECTA family (ERf) receptors have previously been linked with stomata development, above-ground organ elongation, shoot apical meristem function, flower differentiation and biotic/abiotic stresses. Here we explore the role of these genes during embryogenesis. ERfs are expressed in the developing embryo, where their expression is progressively limited to the upper half of the embryo. During embryogenesis ERfs redundantly stimulate the growth of cotyledons by promoting cell proliferation and inhibiting premature stomata differentiation. PMID:25240196

Chen, Ming-Kun; Shpak, Elena D

2014-11-01

393

[Specific features of early embryogenesis in apomictic Poa pratensis L].  

PubMed

We studied the early stages of embryo formation in apomictic Poa partensis L. It was shown that during transition to parthenogenesis, at least at the initial stages of embryogenesis, the algorithm of development of the sexual embryo is preserved. This could be due to the system of genetic control of embryogenesis, common for amphimixis and apomixis. We described asynchrony of developmental processes both within the efflorescence (asynchronous maturation of ovules) and within the ovule and even gametophyte (different timing of induction of apoarchesporic initials and oospores). This feature of pseudogamous apomicts allows them to produce simultaneously both sexual and apomictic progenies. PMID:17352289

Iudakova, O I; Shakina, T N

2007-01-01

394

Somatic mutation, genomic variation, and neurological disease.  

PubMed

Genetic mutations causing human disease are conventionally thought to be inherited through the germ line from one's parents and present in all somatic (body) cells, except for most cancer mutations, which arise somatically. Increasingly, somatic mutations are being identified in diseases other than cancer, including neurodevelopmental diseases. Somatic mutations can arise during the course of prenatal brain development and cause neurological disease-even when present at low levels of mosaicism, for example-resulting in brain malformations associated with epilepsy and intellectual disability. Novel, highly sensitive technologies will allow more accurate evaluation of somatic mutations in neurodevelopmental disorders and during normal brain development. PMID:23828942

Poduri, Annapurna; Evrony, Gilad D; Cai, Xuyu; Walsh, Christopher A

2013-07-01

395

Somatic Mutation, Genomic Variation, and Neurological Disease  

PubMed Central

Genetic mutations causing human disease are conventionally thought to be inherited through the germ line from one’s parents and present in all somatic (body) cells, except for most cancer mutations, which arise somatically. Increasingly, somatic mutations are being identified in diseases other than cancer, including neurodevelopmental diseases. Somatic mutations can arise during the course of prenatal brain development and cause neurological disease—even when present at low levels of mosaicism, for example—resulting in brain malformations associated with epilepsy and intellectual disability. Novel, highly sensitive technologies will allow more accurate evaluation of somatic mutations in neurodevelopmental disorders and during normal brain development. PMID:23828942

Poduri, Annapurna; Evrony, Gilad D.; Cai, Xuyu; Walsh, Christopher A.

2014-01-01

396

Plant regeneration of Korean wild ginseng (Panax ginseng Meyer) mutant lines induced by ?-irradiation ((60)Co) of adventitious roots.  

PubMed

An efficient in vitro protocol has been established for somatic embryogenesis and plantlet conversion of Korean wild ginseng (Panax ginseng Meyer). Wild-type and mutant adventitious roots derived from the ginseng produced calluses on Murashige and Skoog (MS) medium supplemented with 0.5 mg/L 2,4-dichlorophenoxyacetic acid and 0.3 mg/L kinetin; 53.3% of the explants formed callus. Embryogenic callus proliferation and somatic embryo induction occurred on MS medium containing 0.5 mg/L 2,4-dichlorophenoxyacetic acid. The induced somatic embryos further developed to maturity on MS medium with 5 mg/L gibberellic acid, and 85% of them germinated. The germinated embryos were developed to shoots and elongated on MS medium with 5 mg/L gibberellic acid. The shoots developed into plants with well-developed taproots on one-third strength Schenk and Hildebrandt basal medium supplemented with 0.25 mg/L 1-naphthaleneacetic acid. When the plants were transferred to soil, about 30% of the regenerated plants developed into normal plants. PMID:25378998

Zhang, Jun-Ying; Sun, Hyeon-Jin; Song, In-Ja; Bae, Tae-Woong; Kang, Hong-Gyu; Ko, Suk-Min; Kwon, Yong-Ik; Kim, Il-Woung; Lee, Jaechun; Park, Shin-Young; Lim, Pyung-Ok; Kim, Yong Hwan; Lee, Hyo-Yeon

2014-07-01

397

Marker genes identify three somatic cell types in the fetal mouse ovary.  

PubMed

The two main functions of the ovary are the production of oocytes, which allows the continuation of the species, and secretion of female sex hormones, which control many aspects of female development and physiology. Normal development of the ovaries during embryogenesis is critical for their function and the health of the individual in later life. Although the adult ovary has been investigated in great detail, we are only starting to understand the cellular and molecular biology of early ovarian development. Here we show that the adult stem cell marker Lgr5 is expressed in the cortical region of the fetal ovary and this expression is mutually exclusive to FOXL2. Strikingly, a third somatic cell population can be identified, marked by the expression of NR2F2, which is expressed in LGR5- and FOXL2 double-negative ovarian somatic cells. Together, these three marker genes label distinct ovarian somatic cell types. Using lineage tracing in mice, we show that Lgr5-positive cells give rise to adult cortical granulosa cells, which form the follicles of the definitive reserve. Moreover, LGR5 is required for correct timing of germ cell differentiation as evidenced by a delay of entry into meiosis in Lgr5 loss-of-function mutants, demonstrating a key role for LGR5 in the differentiation of pre-granulosa cells, which ensure the differentiation of oogonia, the formation of the definitive follicle reserve, and long-term female fertility. PMID:25158167

Rastetter, Raphael H; Bernard, Pascal; Palmer, James S; Chassot, Anne-Amandine; Chen, Huijun; Western, Patrick S; Ramsay, Robert G; Chaboissier, Marie-Christine; Wilhelm, Dagmar

2014-10-15

398

Intergeneric somatic hybrid plants of Citrus sinensis cv. Hamlin and Poncirus trifoliata cv. Flying Dragon.  

PubMed

Intergeneric somatic hybrid plants between 'Hamlin' sweet orange [Citrus sinensis (L.) Osbeck] and 'Flying Dragon' trifoliate orange (Poncirus trifoliata Raf.) were regenerated following protoplast fusion. 'Hamlin' protoplasts, isolated from an habituated embryogenic suspension culture, were fused chemically with 'Flying Dragon' protoplasts isolated from juvenile leaf tissue. The hybrid selection scheme was based on complementation of the regenerative ability of the 'Hamlin' protoplasts with the subsequent expression of the trifoliate leaf character of 'Flying Dragon.' Hybrid plants were regenerated via somatic embryogenesis and multiplied organogenically. Hybrid morphology was intermediate to that of the parents. Chromosome counts indicated that the hybrids were allotetraploids (2n=4x=36). Malate dehydrogenase (MDH) isozyme patterns confirmed the hybrid nature of the regenerated plants. These genetically unique somatic hybrid plants will be evaluated for citrus rootstock potential. The cell fusion, selection, and regeneration scheme developed herein should provide a general means to expand the germplasm base of cultivated Citrus by intergeneric hybridization with related sexually incompatible genera. PMID:24241403

Grosser, J W; Gmitter, F G; Chandler, J L

1988-01-01

399

Gene function in mouse embryogenesis: get set for gastrulation  

Microsoft Academic Search

During early mouse embryogenesis, temporal and spatial regulation of gene expression and cell signalling influences lineage specification, embryonic polarity, the patterning of tissue progenitors and the morphogenetic movement of cells and tissues. Uniquely in mammals, the extraembryonic tissues are the source of signals for lineage specification and tissue patterning. Here we discuss recent discoveries about the lead up to gastrulation,

David A. F. Loebel; Patrick P. L. Tam

2007-01-01

400

Fetal Alcohol Syndrome: Embryogenesis in a Mouse Model  

Microsoft Academic Search

When two small doses of ethanol were administered to pregnant mice during the gastrulation stage of embryogenesis, the embryos developed craniofacial malformations closely resembling those seen in the human fetal alcohol syndrome. Striking histological changes appeared in the developing brain (neuroectoderm) within 24 hours of exposure. Decreased development of the neural plate and its derivatives apparently accounts for the craniofacial

Kathleen K. Sulik; Malcolm C. Johnston; Mary A. Webb

1981-01-01

401

DNA sequences that activate isocitrate lyase gene expression during late embryogenesis and during postgerminative growth.  

PubMed Central

We analyzed DNA sequences that regulate the expression of an isocitrate lyase gene from Brassica napus L. during late embryogenesis and during postgerminative growth to determine whether glyoxysomal function is induced by a common mechanism at different developmental stages. beta-Glucuronidase constructs were used both in transient expression assays in B. napus and in transgenic Arabidopsis thaliana to identify the segments of the isocitrate lyase 5' flanking region that influence promoter activity. DNA sequences that play the principal role in activating the promoter during post-germinative growth are located more than 1,200 bp upstream of the gene. Distinct DNA sequences that were sufficient for high-level expression during late embryogenesis but only low-level expression during postgerminative growth were also identified. Other parts of the 5' flanking region increased promoter activity both in developing seed and in seedlings. We conclude that a combination of elements is involved in regulating the isocitrate lyase gene and that distinct DNA sequences play primary roles in activating the gene in embryos and in seedlings. These findings suggest that different signals contribute to the induction of glyoxysomal function during these two developmental stages. We also showed that some of the constructs were expressed differently in transient expression assays and in transgenic plants. PMID:8934622

Zhang, J Z; Santes, C M; Engel, M L; Gasser, C S; Harada, J J

1996-01-01

402

Plant regeneration from alginate-encapsulated somatic embryos of Dalbergia sissoo Roxb  

Microsoft Academic Search

A method has been developed for plant regeneration by encapsulation of somatic embryos obtained from callus cultures derived from semi-mature cotyledon explants of Dalbergia sissoo Roxb. (family Fabaceae). Embryogenic callus was developed from cotyledon pieces on Murashige and Skoog (1962) medium supplemented with 9.04 ?M 2,4- dichlorophenoxyacetic acid and 0.46 ?M kinetin. The somatic embryos were induced from embryogenic callus

Ajay Kumar Singh; Suresh Chand

2010-01-01

403

Transformation of white spruce ( Picea glauca) somatic embryos by microprojectile bombardment  

Microsoft Academic Search

Cotyledonary somatic embryos of white spruce [Picea glauca (Moench) Voss] were subjected to microprojectile bombardment with a gene construct containing a gus::nptll fusion gene. Somatic embryos were used to re-induce the embryogenic tissue after bombardments. Histochemical assay using X-gluc as a substrate showed that all the embryos (100%) were GUS positive 48 h after bombardment. However, only thirteen out of

V. R. Bommineni; R. N. Chibbar; R. S. S. Datla; E. W. T. Tsang

1993-01-01

404

Attachment in romantic relationships and somatization.  

PubMed

Adult attachment representations have been considered to play a role in the development and treatment of somatizing behavior. In this study, the associations between the two attachment dimensions avoidance and anxiety and dimensions of psychopathology (somatization, depression, and general anxiety) were explored. The sample consists of 202 outpatients diagnosed with a somatoform disorder. Data were collected via self-report measures. A path analysis shows that the two attachment dimensions are not directly associated with somatization. There are, however, significant indirect associations between attachment and somatization mediated by depression and general anxiety, which are more pronounced for attachment anxiety than for attachment avoidance. The findings reveal that a low level of attachment security in romantic relationships, especially an anxious stance toward the partner, comes along with poor mental health, which in turn is related to a preoccupation with somatic complaints. Implications for the treatment of somatizing patients are discussed. PMID:25594785

Neumann, Eva; Sattel, Heribert; Gündel, Harald; Henningsen, Peter; Kruse, Johannes

2015-02-01

405

Do somatic markers need to be somatic? Analogies from evolution and from hardware interlocks  

E-print Network

Do somatic markers need to be somatic? Analogies from evolution and from hardware interlocks Colin with the concept of hardware interlocks in safety-critical systems. This is used to suggest why it is important of hardware interlocks in engineering design. 2 Could "somatic" markers extend beyond the body? Why do markers

Kent, University of

406

Cracking the egg: virtual embryogenesis of real robots.  

PubMed

All multicellular living beings are created from a single cell. A developmental process, called embryogenesis, takes this first fertilized cell down a complex path of reproduction, migration, and specialization into a complex organism adapted to its environment. In most cases, the first steps of the embryogenesis take place in a protected environment such as in an egg or in utero. Starting from this observation, we propose a new approach to the generation of real robots, strongly inspired by living systems. Our robots are composed of tens of specialized cells, grown from a single cell using a bio-inspired virtual developmental process. Virtual cells, controlled by gene regulatory networks, divide, migrate, and specialize to produce the robot's body plan (morphology), and then the robot is manually built from this plan. Because the robot is as easy to assemble as Lego, the building process could be easily automated. PMID:24730763

Cussat-Blanc, Sylvain; Pollack, Jordan

2014-01-01

407

Systematic determination of patterns of gene expression during Drosophila embryogenesis  

Microsoft Academic Search

BACKGROUND: Cell-fate specification and tissue differentiation during development are largely achieved by the regulation of gene transcription. RESULTS: As a first step to creating a comprehensive atlas of gene-expression patterns during Drosophila embryogenesis, we examined 2,179 genes by in situ hybridization to fixed Drosophila embryos. Of the genes assayed, 63.7% displayed dynamic expression patterns that were documented with 25,690 digital

Pavel Tomancak; Amy Beaton; Richard Weiszmann; Elaine Kwan; ShengQiang Shu; Suzanna E Lewis; Stephen Richards; Michael Ashburner; Volker Hartenstein; Susan E Celniker; Gerald M Rubin

2002-01-01

408

Axes, planes and tubes, or the geometry of embryogenesis  

Microsoft Academic Search

The paper presents selected figures of chick embryogenesis as depicted in the classic studies of Caspar Friedrich Wolff (1734–1794), Christian Heinrich Pander (1794–1865) and Karl Ernst von Baer (1792–1786). My main objective here is (1) to demonstrate how the imagery of Wolff, Pander and Baer attempted to project an image of a 3-dimensional rotating body into static figures on paper

Sabine Brauckmann

2011-01-01

409

Embryogenesis from cultured immature inflorescences and nodes of Lolium multiflorum  

Microsoft Academic Search

When cultured on agar-solidified media (based on Murashige and Skoog's formula), immature inflorescences and nodes ofLolium multiflorum underwent several different pathways of morphogenesis. The pathway expressed was dependent upon the type of explant, its\\u000a age and the composition of the culture medium. Immature inflorescences generally produced either leaves and roots or embryoids\\u000a whereas nodes produced axillary shoots or embryoids. Embryogenesis

P. J. Dale; E. Thomas; R. I. S. Brettell; W. Wernicke

1981-01-01

410

Diverse roles of actin in C. elegans early embryogenesis  

PubMed Central

Background The actin cytoskeleton plays critical roles in early development in Caenorhabditis elegans. To further understand the complex roles of actin in early embryogenesis we use RNAi and in vivo imaging of filamentous actin (F-actin) dynamics. Results Using RNAi, we found processes that are differentially sensitive to levels of actin during early embryogenesis. Mild actin depletion shows defects in cortical ruffling, pseudocleavage, and establishment of polarity, while more severe depletion shows defects in polar body extrusion, cytokinesis, chromosome segregation, and eventually, egg production. These defects indicate that actin is required for proper oocyte development, fertilization, and a wide range of important events during early embryogenesis, including proper chromosome segregation. In vivo visualization of the cortical actin cytoskeleton shows dynamics that parallel but are distinct from the previously described myosin dynamics. Two distinct types of actin organization are observed at the cortex. During asymmetric polarization to the anterior, or the establishment phase (Phase I), actin forms a meshwork of microfilaments and focal accumulations throughout the cortex, while during the anterior maintenance phase (Phase II) it undergoes a morphological transition to asymmetrically localized puncta. The proper asymmetric redistribution is dependent on the PAR proteins, while both asymmetric redistribution and morphological transitions are dependent upon PFN-1 and NMY-2. Just before cytokinesis, actin disappears from most of the cortex and is only found around the presumptive cytokinetic furrow. Finally, we describe dynamic actin-enriched comets in the early embryo. Conclusion During early C. elegans embryogenesis actin plays more roles and its organization is more dynamic than previously described. Morphological transitions of F-actin, from meshwork to puncta, as well as asymmetric redistribution, are regulated by the PAR proteins. Results from this study indicate new insights into the cellular and developmental roles of the actin cytoskeleton. PMID:18157918

Velarde, Nathalie; Gunsalus, Kristin C; Piano, Fabio

2007-01-01

411

Somatic p16INK4a loss accelerates melanomagenesis  

PubMed Central

Loss of p16INK4a–RB and ARF–p53 tumor suppressor pathways, as well as activation of RAS–RAF signaling, is seen in a majority of human melanomas. Although heterozygous germline mutations of p16INK4a are associated with familial melanoma, most melanomas result from somatic genetic events: often p16INK4a loss and N-RAS or B-RAF mutational activation, with a minority possessing alternative genetic alterations such as activating mutations in K-RAS and/or p53 inactivation. To generate a murine model of melanoma featuring some of these somatic genetic events, we engineered a novel conditional p16INK4a-null allele and combined this allele with a melanocyte-specific, inducible CRE recombinase strain, a conditional p53-null allele and a loxP-stop-loxP activatable oncogenic K-Ras allele. We found potent synergy between melanocyte-specific activation of K-Ras and loss of p16INK4a and/or p53 in melanomagenesis. Mice harboring melanocyte-specific activated K-Ras and loss of p16INK4a and/or p53 developed invasive, unpigmented and nonmetastatic melanomas with short latency and high penetrance. In addition, the capacity of these somatic genetic events to rapidly induce melanomas in adult mice suggests that melanocytes remain susceptible to transformation throughout adulthood. PMID:20697345

Monahan, K B; Rozenberg, G I; Krishnamurthy, J; Johnson, S M; Liu, W; Bradford, M K; Horner, J; DePinho, R A; Sharpless, N E

2010-01-01

412

Interactions between ?-tocopherol, polyunsaturated fatty acids, and lipoxygenases during embryogenesis.  

PubMed

?-Tocopherol is a lipid-soluble antioxidant that is specifically required for reproduction and embryogenesis. However, since its discovery, ?-tocopherol's specific biologic functions, other than as an antioxidant, and the mechanism(s) mediating its requirement for embryogenesis remain unknown. As an antioxidant, ?-tocopherol protects polyunsaturated fatty acids (PUFAs) from lipid peroxidation. ?-Tocopherol is probably required during embryonic development to protect PUFAs that are crucial to development, specifically arachidonic (ARA) and docosahexaenoic (DHA) acids. Additionally, ARA and DHA are metabolized to bioactive lipid mediators via lipoxygenase enzymes, and ?-tocopherol may directly protect, or it may mediate the production and/or actions of, these lipid mediators. In this review, we discuss how ?-tocopherol (1) prevents the nonspecific, radical-mediated peroxidation of PUFAs, (2) functions within a greater antioxidant network to modulate the production and/or function of lipid mediators derived from 12- and 12/15-lipoxygenases, and (3) modulates 5-lipoxygenase activity. The application and implication of such interactions are discussed in the context of ?-tocopherol requirements during embryogenesis. PMID:23920314

Lebold, Katie M; Traber, Maret G

2014-01-01

413

[Yamanaka's factors and core transcription factors--the molecular link between embryogenesis and carcinogenesis].  

PubMed

Oct4 and Sox2 transcription factors (belonging to the Yamanaka's factor family) and Nanog, named together as core transcription factors of pluripotency, are indispensable to induce and maintain the pluripotency state. They act generally as activators of genes coding for transcription factors, cofactors and chromatin regulators. They also activate microRNA expression. In addition, Oct4, Sox2 and Nanog function as repressors of genes for factors responsible for escape from pluripotency and differentiation. Core transcription factors positively regulate their own promoters, forming a positive-feedback loop. In recent times, researchers' attention has been attracted towards Oct4, Sox2 and Nanog as potential markers for cancer stem cells (CSCs). The expression of these factors has been confirmed in numerous types of tumors. The aim of this paper is to concisely review features of core transcription factors and their role in embryogenesis and tumorigenesis including the CSC hypothesis. PMID:24934529

Fu?awka, ?ukasz; Donizy, Piotr; Ha?o?, Agnieszka

2014-01-01

414

Visceral versus Somatic Pain: Similarities and Differences  

Microsoft Academic Search

Inflammatory bowel disease and the irritable bowel syndrome are conditions characterized by chronic pain that generates persistent, hyperalgesic states in many regions of the body. It is difficult to explain the pain of conditions such as inflammatory bowel disease and irritable bowel syndrome by extrapolating directly from what is known about the mechanisms of somatic pain. Visceral and somatic pain

Fernando Cervero

2009-01-01

415

Plant pathology Difference in somatic embryogenetic ability  

E-print Network

Plant pathology Difference in somatic embryogenetic ability of cultured leaf explants of four explants forming somatic embryos varied from 15.2-90.3, mean number of plants regenerat- ed/explant from 1.5-29.5. In terms of their embryogenic competence and plant regeneration the genotypes could be rated in decreasing

Boyer, Edmond

416

Abscisic acid induction of cloned cotton late embryogenesis-abundant (Lea) mRNAs  

Microsoft Academic Search

Earlier studies found that cotton (Gossypium hirsutum L.) cotyledons contain several mRNAs which are more abundant during late embryogenesis than in mid-embryogenesis or early germination. They are here termed ‘Late embryogenesis-abundant’ mRNAs, encoded by Lea loci. Complementary DNA clones for 18 such mRNA sequences, defined at a hybridization criterion of Tm-15°C, were identified in a mature embryo cDNA library by

Glenn A. Galau; D. Wayne Hughes; Leon Dure

1986-01-01

417

Embryogenesis and plant regeneration from isolated microspores of Brassica rapa L. ssp. Oleifera  

Microsoft Academic Search

Summary  Conditions favourable to embryogenesis from isolated microspores of Brassica rapa L. ssp. oleifera (canola quality) were identified. A population with enhanced responsiveness for microspore embryogenesis (C200) was synthesized by crossing individual plants showing microspore embryogenic potential. For optimal microspore embryogenesis, buds (2–3mm in length, containing mid-late uninucieate microspores) were collected from older plants (2 months old) and microspores isolated and

Laurie Burnett; Stephen Yarrow; Bin Huang

1992-01-01

418

The effect of several factors on somatic embryogenesis and plant regeneration in protoplast cultures of Gentiana kurroo (Royle)  

Microsoft Academic Search

Protoplasts were isolated from cell suspensions derived from cotyledon and hypocotyl Gentiana kurroo (Royle). Cell walls were digested with an enzyme cocktail containing cellulase, macerozyme, driselase, hemicellulase and\\u000a pectolyase in CPW solution. Protoplast viability ranged from 88 to 96%. Three techniques of culture and six media were evaluated\\u000a in terms of their efficiency in producing viable cultures and regenerating whole

Agnieszka Fiuk; Jan J. Rybczy?ski

2007-01-01

419

Establishment of suspension cultures from seeds of plains bluestem [ Bothriochloa ischaemum (L.) Keng.] and regeneration of plants via somatic embryogenesis  

Microsoft Academic Search

Summary  Mature seeds of plains Old World bluestem [Bothriochloa ischaemum (L.) Keng.] were used to initiate suspension cultures. The medium contained the major and minor minerals of Murashige and\\u000a Skoog, Gamborg's B-5 vitamins, 30 g\\/liter sucrose, and 3 mg\\/liter 2,4-dichlorophenoxyacetic acid with or without 12 mM proline at pH 5.5. Cultures contained both embryogenic and nonembryogenic (NE) cells. Suspensions that had

BECKY B. JOHNSONAND; Martin Worthington

1987-01-01

420

In vitro regeneration of Echinacea purpurea L.: Direct somatic embryogenesis and indirect shoot organogenesis in petiole culture  

Microsoft Academic Search

Summary  An in vitro propagation system was developed for Echinacea purpurea L. (purple coneflower), a medicinal plant commonly used in the treatment of colds, flu and related ailments. Echinacea seeds were found to be contaminated with systemic fungi and therefore an optimized minimal concentration of Plant Preservation\\u000a Mixture (PPM) was incorporated in the seed germination medium to recover sterile seedlings. Regeneration

Kristen L. Choffe; Jerrin M. R. Victor; Susan J. Murch; Praveen K. Saxena

2000-01-01

421

In vitro regeneration of chickpea (Cicer arietinum L.): Stimulation of direct organogenesis and somatic embryogenesis by thidiazuron  

Microsoft Academic Search

In vitro regeneration in chickpea (Cicer arietinum L.) was achieved by direct culture of mature seeds on Murashige and Skoog (MS) medium supplemented with either N-phenyl-N'(-1,2,3-thidiazol-5-yl) urea (thidiazuron, TDZ) or N6-benzylaminopurine (BAP). Multiple shoots formed de novo without an intermediary callus phase at the cotyledonary notch region of the seedlings within 2 to 3 weeks of culture initiation. TDZ was

B. N. S. Murthy; Jerrin Victor; Rana P. Singh; R. A. Fletcher; Praveen K. Saxena

1996-01-01

422

Induction of somatic embryogenesis and plant regeneration in the tropical timber tree Spanish red cedar [ Cedrela odorata L. (Meliaceae)  

Microsoft Academic Search

Spanish red cedar (Cedrela\\u000a odorata L.) is a tropical timber tree native to the Americas from southern Mexico to northern Argentina. Commercial plantations are\\u000a scarce and, consequently, natural populations are overexploited. Traditional propagation practices for the establishment of\\u000a large-scale plantations have had limited success in this species due to the relative scarcity of seeds, its broad genetic\\u000a diversity and the

Yuri J. Peńa-Ramírez; Israel García-Sheseńa; Ángel Hernández-Espinoza; Alfredo Domínguez-Hernández; Felipe A. Barredo-Pool; José A. González-Rodríguez; Manuel L. Robert

2011-01-01

423

Somatic embryogenesis and plant regeneration from root segments of Psoralea corylifolia L., an endangered medicinally important plant  

Microsoft Academic Search

Summary  An efficient plant regeneration protocol has been developed from root explants of Psoralea corylifolia L., an endangered medicinally\\u000a important herbaceous plant species belonging to the family Fabaceae. Nodular embryogenic callus was initiated from young root\\u000a segments cultured on Murashige and Skoog (MS) medium (1962) supplemented with ?-naphthaleneacetic acid (NAA; 2.68–13.42 ?M)\\u000a or 2,4-dichlorophenoxyacetic acid (2.4-D; 2.25–11.25 ?M) in combination with

Suresh Chand; Ashok Kumar Sahrawat

2002-01-01

424

Rapid and efficient transformation of diploid Medicago truncatula and Medicago sativa ssp. falcata lines improved in somatic embryogenesis  

Microsoft Academic Search

We describe a simple and efficient protocol for regeneration-transformation of two diploid Medicago lines: the annual M. truncatula R108-1(c3) and the perennial M. sativa ssp. falcata (L.) Arcangeli PI.564263 selected previously as highly embryogenic genotypes. Here, embryo regeneration of R108-1 to complete\\u000a plants was further improved by three successive in vitro regeneration cycles resulting in the line R108-1(c3). Agrobacterium tumefaciens-mediated

T. H. Trinh; P. Ratet; E. Kondorosi; P. Durand; K. Kamaté; P. Bauer; A. Kondorosi

1998-01-01

425

Plant regeneration from cultured immature embryos and inflorescences of Triticum aestivum L. (wheat): Evidence for somatic embryogenesis  

Microsoft Academic Search

Summary Tissue cultures ofTriticum aestivum L. (wheat) initiated from young inflorescences and immature embryos possessed the potential for regeneration of whole plants. Both a friable and a compact type of callus were produced on Murashige and Skoog's medium with 2 mg\\/l 2,4-dichlorophenoxyacetic acid. The friable callus contained meristematic centers in which the peripheral cells ceased dividing, elongated, and could be

Peggy Ozias-Akins; Indra K. Vasil

1982-01-01

426

Somatic Mutations in Aging, Cancer and Neurodegeneration  

PubMed Central

The somatic mutation theory of aging posits that the accumulation of mutations in the genetic material of somatic cells as a function of time results in a decrease in cellular function. In particular, the accumulation of random mutations inactivates genes that are important for the functioning of the somatic cells of various organ systems of the adult, which results in a decrease in organ function. When the organ function decreases below a critical level, death occurs. A significant amount of research has shown that somatic mutations play an important role in aging and a number of age related pathologies. In this review, we explore evidence for increases in somatic nuclear mutation burden with age and the consequences for aging, cancer, and neurodegeneration. We then review evidence for increases in mitochondrial mutation burden and the consequences for dysfunction in the disease processes. PMID:22079405

Kennedy, Scott R.; Loeb, Lawrence A.; Herr, Alan J.

2012-01-01

427

Somatic Mosaicism in the Human Genome  

PubMed Central

Somatic mosaicism refers to the occurrence of two genetically distinct populations of cells within an individual, derived from a postzygotic mutation. In contrast to inherited mutations, somatic mosaic mutations may affect only a portion of the body and are not transmitted to progeny. These mutations affect varying genomic sizes ranging from single nucleotides to entire chromosomes and have been implicated in disease, most prominently cancer. The phenotypic consequences of somatic mosaicism are dependent upon many factors including the developmental time at which the mutation occurs, the areas of the body that are affected, and the pathophysiological effect(s) of the mutation. The advent of second-generation sequencing technologies has augmented existing array-based and cytogenetic approaches for the identification of somatic mutations. We outline the strengths and weaknesses of these techniques and highlight recent insights into the role of somatic mosaicism in causing cancer, neurodegenerative, monogenic, and complex disease. PMID:25513881

Freed, Donald; Stevens, Eric L.; Pevsner, Jonathan

2014-01-01

428

Somatic embryo mediated mass production of Catharanthus roseus in culture vessel (bioreactor) - A comparative study.  

PubMed

The purpose of this study was to evaluate and compare the use of liquid and solid Murashige and Skoog (MS) medium in different culture vessels for mass production of Catharanthus roseus, an important source of anticancerous compounds, vincristine and vinblastine. Three media conditions i.e. agar-solidified medium (S), liquid medium in agitated conical flask (L) and growtek bioreactor (B) were used. Rapid propagation was achieved through in vitro somatic embryogenesis pathway. The process of embryogenesis has been categorized into induction, proliferation, maturation and germination stages. All in vitro embryogenesis stages were conducted by withdrawing spent liquid medium and by adding fresh MS medium. In optimized 4.52 ?M 2,4-D added MS, the callus biomass growth was low in solid (1.65 g) compared to liquid medium in agitated conical flask (1.95 g) and in bioreactor (2.11 g). The number of normal somatic embryos was more in solid medium (99.75/50 mg of callus mass) compared to liquid medium used in conical flask (83.25/callus mass) and growtek bioreactor (84.88/callus mass). The in vitro raised embryos maturated in GA3 (2.60 ?M) added medium; and in bioreactor the embryo growth was high, a maximum length of 9.82 mm was observed at the end of four weeks. These embryos germinated into seedlings in BAP (2.22 ?M) added medium and the embryo germination ability was more (59.41%) in bioreactor compared to liquid medium in conical flask (55.5%). Shoot length (11.25 mm) was also high in bioreactor compared to agitated conical flask. The liquid medium used in agitated conical flask and bioreactor increased seedling production efficiency, at the same time it also reduced plant recovery time. The embryo generated plants grew normally in outdoor conditions. The exploitation of medium to large culture vessel or bioreactor may make the process more efficient in getting large number of Catharanthus plant as it is the only source of anti-cancerous alkaloids, vincristine and vinblastine. PMID:25313279

Mujib, A; Ali, Muzamil; Isah, Tasiu; Dipti

2014-11-01

429

Encapsulation for somatic gene therapy.  

PubMed

With the human genome project approaching its completion date of 2005, gene-based technology will play an increasingly important role in health-care delivery. Non-autologous somatic gene therapy is a novel application in which non-autologous cell lines engineered to secrete a recombinant protein are enclosed within immunoisolation devices and implanted into all patients requiring the same product for therapy. The development of this technology requires a multi-disciplinary effort towards optimization of the biomaterial used to manufacture the implantable devices and selection of the appropriate cell lines for enclosure. The efficacy of this technology is illustrated in the treatment of dwarfism and lysosomal storage disease in murine models. The potential of a safe and cost-effective gene-based delivery method should have wide applications in treating both classical genetic disorders and non-Mendelian diseases. PMID:10415564

Chang, P L

1999-06-18

430

Somatic Treatments for Mood Disorders  

PubMed Central

Somatic treatments for mood disorders represent a class of interventions available either as a stand-alone option, or in combination with psychopharmacology and/or psychotherapy. Here, we review the currently available techniques, including those already in clinical use and those still under research. Techniques are grouped into the following categories: (1) seizure therapies, including electroconvulsive therapy and magnetic seizure therapy, (2) noninvasive techniques, including repetitive transcranial magnetic stimulation, transcranial direct current stimulation, and cranial electric stimulation, (3) surgical approaches, including vagus nerve stimulation, epidural electrical stimulation, and deep brain stimulation, and (4) technologies on the horizon. Additionally, we discuss novel approaches to the optimization of each treatment, and new techniques that are under active investigation. PMID:21976043

Rosa, Moacyr A; Lisanby, Sarah H

2012-01-01

431

E3 ubiquitin ligases promote progression of differentiation during C. elegans embryogenesis.  

PubMed

Regulated choice between cell fate maintenance and differentiation provides decision points in development to progress toward more restricted cell fates or to maintain the current one. Caenorhabditis elegans embryogenesis follows an invariant cell lineage where cell fate is generally more restricted upon each cell division. EMS is a progenitor cell in the four-cell embryo that gives rise to the endomesoderm. We recently found that when ubiquitin-mediated protein degradation is compromised, the anterior daughter of EMS, namely MS, reiterates the EMS fate. This observation demonstrates an essential function of ubiquitin-mediated protein degradation in driving the progression of EMS-to-MS differentiation. Here we report a genome-wide screen of the ubiquitin pathway and extensive lineage analyses. The results suggest a broad role of E3 ligases in driving differentiation progression. First, we identified three substrate-binding proteins for two Cullin-RING ubiquitin ligase (CRL) E3 complexes that promote the progression from the EMS fate to MS, namely LIN-23/?-TrCP and FBXB-3 for the CRL1/SCF complex and ZYG-11/ZYG-11B for the CRL2 complex. Genetic analyses suggest these E3 ligases function through a multifunctional protein OMA-1 and the endomesoderm lineage specifier SKN-1 to drive differentiation. Second, we found that depletion of components of the CRL1/SCF complex induces fate reiteration in all major founder cell lineages. These data suggest that regulated choice between self-renewal and differentiation is widespread during C. elegans embryogenesis as in organisms with regulative development, and ubiquitin-mediated protein degradation drives the choice towards differentiation. Finally, bioinformatic analysis of time series gene expression data showed that expression of E3 genes is transiently enriched during time windows of developmental stage transitions. Transcription factors show similar enrichment, but not other classes of regulatory genes. Based on these findings we propose that ubiquitin-mediated protein degradation, like many transcription factors, function broadly as regulators driving developmental progression during embryogenesis in C. elegans. PMID:25523393

Du, Zhuo; He, Fei; Yu, Zidong; Bowerman, Bruce; Bao, Zhirong

2015-02-15

432

Hypothesis: Somatic Mosaicism and Parkinson Disease  

PubMed Central

Mutations causing genetic disorders can occur during mitotic cell division after fertilization, which is called somatic mutations. This leads to somatic mosaicism, where two or more genetically distinct cells are present in one individual. Somatic mutations are the most well studied in cancer where it plays an important role and also have been associated with some neurodegenerative disorders. The study of somatic mosaicism in Parkinson disease (PD) is only in its infancy, and a case with somatic mutation has not yet been described. However, we can speculate that a somatic mutation affecting cells in the central nervous system including substantia nigra dopaminergic neurons could lead to the development of PD through the same pathomechanisms of genetic PD even in the absence of a germ-line mutation. Theoretically, a number of genes could be candidates for genetic analysis for the presence of somatic mosaicism. Among them, SNCA and PARK2 could be the best candidates to analyze. Because analyzing brain tissues in living patients is impossible, alternative tissues could be used to indicate the genetic status of the brain. Performance of the technology is another factor to consider when analyzing the tissues. PMID:25548528

Kim, Han-Joon

2014-01-01

433

The use of centrifugation to study early Drosophila embryogenesis  

NASA Technical Reports Server (NTRS)

By the end of 10th nuclear cycle, the somatic nuclei of the Drosophila embryo have migrated to the periphery of the egg. Centrifugation of embryos did not result in the displacement of these nuclei, since cytoskeletal elements anchor them to the cortex. But, mild centrifugal forces displace the centrally located, nascent yolk nuclei. If this increased sensitivity to hypergravity occurs before the beginning of nuclear differentiation during cycle 8, when the nascent yolk and somatic nuclei physically separate, then it would mark the earliest functional difference between these two lineages.

Abbott, M. K.; Spooner, B. S. (Principal Investigator)

1993-01-01

434

Non-stochastic reprogramming from a privileged somatic cell state  

PubMed Central

SUMMARY Reprogramming somatic cells to induced pluripotency by Yamanaka factors is usually slow and inefficient, and is thought to be a stochastic process. We identified a privileged somatic cell state, from which acquisition of pluripotency could occur in a non-stochastic manner. Subsets of murine hematopoietic progenitors are privileged, whose progeny cells predominantly adopt the pluripotent fate with activation of endogenous Oct4 locus after 4–5 divisions in reprogramming conditions. Privileged cells display an ultrafast cell cycle of ~8 hours. In fibroblasts, a subpopulation cycling at a similar ultrafast speed is observed after 6 days of factor expression, and is increased by p53-knockdown. This ultrafast-cycling population accounts for >99% of the bulk reprogramming activity in wildtype or p53-knockdown fibroblasts. Our data demonstrate that the stochastic nature of reprogramming can be overcome in a privileged somatic cell state, and suggest that cell cycle acceleration toward a critical threshold is an important bottleneck for reprogramming. PMID:24486105

Guo, Shangqin; Zi, Xiaoyuan; Schulz, Vincent P.; Cheng, Jijun; Zhong, Mei; Koochaki, Sebastian H.J.; Megyola, Cynthia M.; Pan, Xinghua; Heydari, Kartoosh; Weissman, Sherman M.; Gallagher, Patrick G.; Krause, Diane S.; Fan, Rong; Lu, Jun

2014-01-01

435

Regenerative therapy for neuronal diseases with transplantation of somatic stem cells  

PubMed Central

Pluripotent stem cells, which are capable of differentiating in various species of cells, are hoped to be donor cells in transplantation in regenerative medicine. Embryonic stem (ES) cells and induced pluripotent stem cells have the potential to differentiate in approximately all species of cells. However, the proliferating ability of these cells is high and the cancer formation ability is also recognized. In addition, ethical problems exist in using ES cells. Somatic stem cells with the ability to differentiate in various species of cells have been used as donor cells for neuronal diseases, such as amyotrophic lateral sclerosis, spinal cord injury, Alzheimer disease, cerebral infarction and congenital neuronal diseases. Human mesenchymal stem cells derived from bone marrow, adipose tissue, dermal tissue, umbilical cord blood and placenta are usually used for intractable neuronal diseases as somatic stem cells, while neural progenitor/stem cells and retinal progenitor/stem cells are used for a few congenital neuronal diseases and retinal degenerative disease, respectively. However, non-treated somatic stem cells seldom differentiate to neural cells in recipient neural tissue. Therefore, the contribution to neuronal regeneration using non-treated somatic stem cells has been poor and various differential trials, such as the addition of neurotrophic factors, gene transfer, peptide transfer for neuronal differentiation of somatic stem cells, have been performed. Here, the recent progress of regenerative therapies using various somatic stem cells is described. PMID:24179604

Kanno, Hiroshi

2013-01-01

436

Optimal Ratio of Transcription Factors for Somatic Cell Reprogramming*  

PubMed Central

Somatic cell reprogramming is achieved by four reprogramming transcription factors (RTFs), Oct3/4, Sox2, Klf4, and c-Myc. However, in addition to the induction of pluripotent cells, these RTFs also generate pseudo-pluripotent cells, which do not show Nanog promoter activity. Therefore, it should be possible to fine-tune the RTFs to produce only fully pluripotent cells. For this study, a tagging system was developed to sort induced pluripotent stem (iPS) cells according to the expression levels of each of the four RTFs. Using this system, the most effective ratio (Oct3/4-high, Sox2-low, Klf4-high, c-Myc-high) of the RTFs was 88 times more efficient at producing iPS cells than the worst effective ratio (Oct3/4-low, Sox2-high, Klf4-low, c-Myc-low). Among the various RTF combinations, Oct3/4-high and Sox2-low produced the most efficient results. To investigate the molecular basis, microarray analysis was performed on iPS cells generated under high (Oct3/4-high and Sox2-low) and low (Oct3/4-low and Sox2-high) efficiency reprogramming conditions. Pathway analysis revealed that the G protein-coupled receptor (GPCR) pathway was up-regulated significantly under the high efficiency condition and treatment with the chemokine, C-C motif ligand 2, a member of the GPCR family, enhanced somatic cell reprogramming 12.3 times. Furthermore, data from the analysis of the signature gene expression profiles of mouse embryonic fibroblasts at 2 days after RTF infection revealed that the genetic modifier, Whsc1l1 (variant 1), also improved the efficiency of somatic cell reprogramming. Finally, comparison of the overall gene expression profiles between the high and low efficiency conditions will provide novel insights into mechanisms underlying somatic cell reprogramming. PMID:22955270

Nagamatsu, Go; Saito, Shigeru; Kosaka, Takeo; Takubo, Keiyo; Kinoshita, Taisuke; Oya, Mototsugu; Horimoto, Katsuhisa; Suda, Toshio

2012-01-01

437

Disruption of Circulation by Ethanol Promotes Fetal Alcohol Spectrum Disorder (FASD) in Medaka (Oryzias latipes) Embryogenesis  

PubMed Central

Japanese medaka (Oryzias latipes) embryos exposed to ethanol have developed craniofacial, cardiovascular and skeletal defects which can be compared with the phenotypic features of fetal alcohol spectrum disorder (FASD) observed in human. The present experiment was designed to show that the disruption in circulation by ethanol during embryogenesis is a potential cause of FASD. Fertilized eggs were exposed to ethanol (0, 100 and/or 400 mM) for 24 or 48 h at various developmental stages (Iwamatsu stages 4–30) and were analyzed at 6 day post fertilization (dpf). It was observed that controls and the embryos exposed to 100 mM ethanol were in circulating state; however, a significant number of embryos of stages 4–24 exposed to 400 mM ethanol had disrupted circulation. Compared to controls, protein and RNA contents were significantly reduced in non-circulating embryos. Lipid peroxidation (LPO) analysis was made at 3, 6, 24, 48, 96 and 144 hour post fertilization (hpf). LPO was increased with the advancement of morphogenesis; however, ethanol or the circulation status had no effect. We further analyzed alcohol dehydrogenase (Adh 5 and adh8) and aldehyde dehydrogenase (Aldh9A and Aldh1A2) enzyme mRNAs in the embryos exposed to 400 mM ethanol for 24h. A developmental stage specific reduction in these enzyme mRNAs by ethanol was observed. We conclude that ethanol-induced disruption in circulation during embryogenesis is a potential cause of the development of FASD features in medaka. PMID:18621148

Hu, Yuhui; Khan, Ikhlas A.; Dasmahapatra, Asok K.

2008-01-01

438

Dormancy induction of somatic embryos of Siberian ginseng by high sucrose concentrations enhances the conservation of hydrated artificial seeds and dehydration resistance  

Microsoft Academic Search

. In most plants, somatic embryos tend to germinate prematurely, a process that is detrimental to controlled plant production and the conservation of artificial seeds. We investigated the dormancy characteristics of Siberian ginseng somatic embryos induced simply by a high sucrose treatment, a treatment that enables the long-term conservation of artificial seeds following encapsulation and provides embryos with an enhanced

Y. E. Choi; J. H. Jeong

2002-01-01

439

Predictive models of molecular machines involved in Caenorhabditis elegans early embryogenesis  

Microsoft Academic Search

Although numerous fundamental aspects of development have been uncovered through the study of individual genes and proteins, system-level models are still missing for most developmental processes. The first two cell divisions of Caenorhabditis elegans embryogenesis constitute an ideal test bed for a system-level approach. Early embryogenesis, including processes such as cell division and establishment of cellular polarity, is readily amenable

Kristin C. Gunsalus; Hui Ge; Aaron J. Schetter; Debra S. Goldberg; Jing-Dong J. Han; Tong Hao; Gabriel F. Berriz; Nicolas Bertin; Jerry Huang; Ling-Shiang Chuang; Ning Li; Ramamurthy Mani; Anthony A. Hyman; Birte Sönnichsen; Christophe J. Echeverri; Frederick P. Roth; Marc Vidal; Fabio Piano

2005-01-01

440

Identification of tightly regulated groups of genes during Drosophila melanogaster embryogenesis  

Microsoft Academic Search

Time-series analysis of whole-genome expression data during Drosophila melanogaster development indicates that up to 86% of its genes change their relative transcript level during embryogenesis. By applying conservative filtering criteria and requiring ‘sharp’ transcript changes, we identified 1534 maternal genes, 792 transient zygotic genes, and 1053 genes whose transcript levels increase during embryogenesis. Each of these three categories is dominated

Sean D Hooper; Stephanie Boue ´; Roland Krause; Lars J Jensen; Christopher E Mason; Murad Ghanim; Kevin P White; Eileen EM Furlong; Peer Bork

2007-01-01

441

Cytokinin and auxin interaction in root stem-cell specification during early embryogenesis  

E-print Network

LETTERS Cytokinin and auxin interaction in root stem-cell specification during early embryogenesis during embryogenesis. It has been known for decades that cyto- kinin and auxin interact to control organ regeneration in cultured tissue1 . Auxin has a critical role in root stem-cell specification in zygotic

Sheen, Jen

442

Processed pseudogenes acquired somatically during cancer development  

PubMed Central

Cancer evolves by mutation, with somatic reactivation of retrotransposons being one such mutational process. Germline retrotransposition can cause processed pseudogenes, but whether this occurs somatically has not been evaluated. Here we screen sequencing data from 660 cancer samples for somatically acquired pseudogenes. We find 42 events in 17 samples, especially non-small cell lung cancer (5/27) and colorectal cancer (2/11). Genomic features mirror those of germline LINE element retrotranspositions, with frequent target-site duplications (67%), consensus TTTTAA sites at insertion points, inverted rearrangements (21%), 5? truncation (74%) and polyA tails (88%). Transcriptional consequences include expression of pseudogenes from UTRs or introns of target genes. In addition, a somatic pseudogene that integrated into the promoter and first exon of the tumour suppressor gene, MGA, abrogated expression from that allele. Thus, formation of processed pseudogenes represents a new class of mutation occurring during cancer development, with potentially diverse functional consequences depending on genomic context. PMID:24714652

Cooke, Susanna L.; Shlien, Adam; Marshall, John; Pipinikas, Christodoulos P.; Martincorena, Inigo; Tubio, Jose M.C.; Li, Yilong; Menzies, Andrew; Mudie, Laura; Ramakrishna, Manasa; Yates, Lucy; Davies, Helen; Bolli, Niccolo; Bignell, Graham R.; Tarpey, Patrick S.; Behjati, Sam; Nik-Zainal, Serena; Papaemmanuil, Elli; Teixeira, Vitor H.; Raine, Keiran; O’Meara, Sarah; Dodoran, Maryam S.; Teague, Jon W.; Butler, Adam P.; Iacobuzio-Donahue, Christine; Santarius, Thomas; Grundy, Richard G.; Malkin, David; Greaves, Mel; Munshi, Nikhil; Flanagan, Adrienne M.; Bowtell, David; Martin, Sancha; Larsimont, Denis; Reis-Filho, Jorge S.; Boussioutas, Alex; Taylor, Jack A.; Hayes, Neil D.; Janes, Sam M.; Futreal, P. Andrew; Stratton, Michael R.; McDermott, Ultan; Campbell, Peter J.; Provenzano, Elena; van de Vijver, Marc; Richardson, Andrea L.; Purdie, Colin; Pinder, Sarah; Mac Grogan, Gaetan; Vincent-Salomon, Anne; Larsimont, Denis; Grabau, Dorthe; Sauer, Torill; Garred, Řystein; Ehinger, Anna; Van den Eynden, Gert G.; van Deurzen, C.H.M; Salgado, Roberto; Brock, Jane E.; Lakhani, Sunil R.; Giri, Dilip D.; Arnould, Laurent; Jacquemier, Jocelyne; Treilleux, Isabelle; Caldas, Carlos; Chin, Suet-Feung; Fatima, Aquila; Thompson, Alastair M.; Stenhouse, Alasdair; Foekens, John; Martens, John; Sieuwerts, Anieta; Brinkman, Arjen; Stunnenberg, Henk; Span, Paul N.; Sweep, Fred; Desmedt, Christine; Sotiriou, Christos; Thomas, Gilles; Broeks, Annegein; Langerod, Anita; Aparicio, Samuel; Simpson, Peter T.; van ’t Veer, Laura; Erla Eyfjörd, Jórunn; Hilmarsdottir, Holmfridur; Jonasson, Jon G.; Břrresen-Dale, Anne-Lise; Lee, Ming Ta Michael; Wong, Bernice Huimin; Tan, Benita Kiat Tee; Hooijer, Gerrit K.J.

2014-01-01

443

Somatic retrotransposition in the cancer genome  

E-print Network

Cancer is a complex disease of the genome exhibiting myriad somatic mutations, from single nucleotide changes to various chromosomal rearrangements. The technological advances of next-generation sequencing enable high-throughput ...

Helman, Elena

2014-01-01

444

Progress in the reprogramming of somatic cells  

PubMed Central

Pluripotent stem cells can differentiate into nearly all types of cells in the body. This unique potential provides significant promise for cell-based therapies to restore tissues or organs destroyed by injuries, degenerative diseases, aging, or cancer. The discovery of induced pluripotent stem cell (iPSC) technology offers a possible strategy to generate patient-specific pluripotent stem cells. However, because of concerns about the specificity, efficiency, kinetics, and safety of iPSC reprogramming, improvements or fundamental changes in this process are required before their effective clinical use. A chemical approach is regarded as a promising strategy to improve and change the iPSC process. Dozens of small molecules have been identified that can functionally replace reprogramming factors and significantly improve iPSC reprogramming. In addition to the prospect of deriving patient-specific tissues and organs from iPSCs, another attractive strategy for regenerative medicine is transdifferentiation—the direct conversion of one somatic cell type to another. Recent studies revealed a new paradigm of transdifferentiation: using transcription factors (TFs) employed in iPSC generation to induce transdifferentiation, or iPSC TF-based transdifferentiation. This transdifferentiation not only reveals and utilizes the developmentally plastic intermediates generated during iPSC reprogramming, but also produces a very wide range of cells, including expandable tissue-specific precursor cells. Here, we review recent progress of small-molecule approaches in the generation of iPSCs. In addition, we summarize the new concept of iPSC TF–based transdifferentiation and discuss its application in generating various lineage-specific cells, especially cardiovascular cells. PMID:23371904

Ma, Tianhua; Xie, Min; Laurent, Timothy; Ding, Sheng

2013-01-01

445

Vasoactive intestinal peptide antagonist treatment during mouse embryogenesis impairs social behavior and cognitive function of adult male offspring  

Microsoft Academic Search

Vasoactive intestinal peptide (VIP) is a regulator of rodent embryogenesis during the period of neural tube closure. VIP enhanced growth in whole cultured mouse embryos; treatment with a VIP antagonist during embryogenesis inhibited growth and development. VIP antagonist treatment during embryogenesis also had permanent effects on adult brain chemistry and impaired social recognition behavior in adult male mice. The neurological

Joanna M. Hill; Katrina Cuasay; Daniel T. Abebe

2007-01-01

446

Human somatic cell nuclear transfer and cloning.  

PubMed

This document presents arguments that conclude that it is unethical to use somatic cell nuclear transfer (SCNT) for infertility treatment due to concerns about safety; the unknown impact of SCNT on children, families, and society; and the availability of other ethically acceptable means of assisted reproduction. This document replaces the ASRM Ethics Committee report titled, "Human somatic cell nuclear transfer (cloning)," last published in Fertil Steril 2000;74:873-6. PMID:22795681

2012-10-01

447

(Somatic mutations in nuclear and mitochondrial DNA)  

SciTech Connect

The study is concerned the design of new assays that may detect rare somatic mutations in nuclear and mitochondrial DNA, which may increase upon exposure to mutagens, and thus become a marker of human exposure to such mutagens. Two assays for somatic mutation were presented, one for mitochondrial DNA deletions which was developed by the author, and one for deletions of the ADA gene which resides in the nucleus.

Not Available

1992-01-01

448