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Mutants as Tools for the Analytical Dissection of Cell Differentiation in Physcomitrella Patens Gametophytes
Published in R. N. Chopra, Satish C. Bhatla, Bryophyte Development: Physiology and Biochemistry, 2019
The majority of tropically abnormal P. patens strains11,12,19-21 have been obtained, following mutagenesis, by means of nonselective (i.e., total) isolation procedures.22,30 Mutants affected in cell differentiation have been isolated both nonselectively3,4,22 and selectively.4,22 In the nonselective isolation procedure mutagenized spores have been allowed to germinate and grow into gametophytes, which have been examined visually to detect mutants with abnormal morphologies. Many morphologically abnormal strains obtained in this way have been shown subsequently to have altered sensitivities to exogenous auxin and/or cytokinin.4,22 Many mutants isolated selectively by their resistance to concentrations of the synthetic auxin 1-naphthaleneacetic acid (NAA) or the synthetic cytokinin 6-benzylaminopurine (BAP), which cause profound changes in the growth and development of the wild-type, have been found to be altered developmentally even when grown in the absence of exogenous hormones.4,22
Horticultural Management of Syzygium cumini
Published in K. N. Nair, The Genus Syzygium, 2017
S. K. Tewari, Devendra Singh, R. C. Nainwal
There are several methods of culturing plant tissues, such as meristem culture, embryo culture, callus culture, protoplast culture, and cell culture. Yadav et al. (1990) induced multiple shoots from nodal and shoot tip segments of 10- to 15-day-old seedlings of S. cumini on a modified Murashige and Skoog (MS) medium supplemented with β-alanine (BA) singly and in combination with 1-naphthaleneacetic acid (NAA), IAA, or IBA. Excised shoots were placed for root induction on MS medium containing NAA or IBA and then transferred to MS basal medium to form complete plantlets. The regenerated plantlets were acclimatized and successfully transferred to the soil. Roy et al. (1996a,b) induced multiple shoots from nodal explants of 10-year-old elite trees and also from in vitro proliferated shoots of S. cumini on MS medium supplemented with 2.5 mg kinetin/L. Repeated subculture resulted in rapid shoot multiplication at an average of 10 shoots per subculture. Jain and Babbar (2000) obtained multiple shoots from the epicotyl segments bearing scaly leaves, excised from in vitro–grown seedlings of S. cumini, on MS medium supplemented with different concentrations of IBA. On average, 8.6 shoots per explant were produced in 60 days after inoculation, following transfer to fresh medium after 30 days. The shoots were excised and the residual explants were transferred to fresh medium, where they developed shoots again. Thus, a protocol was developed to raise plants of S. cumini at any time in the year. Somatic embryogenesis has also been found to be successful for multiplication of jamun plants.
Green synthesis of silver nanoparticles using transgenic Nicotiana tabacum callus culture expressing silicatein gene from marine sponge Latrunculia oparinae
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Yuri N. Shkryl, Galina N. Veremeichik, Dmitriy G. Kamenev, Tatiana Y. Gorpenchenko, Yulia A. Yugay, Dmitriy V. Mashtalyar, Aleksander V. Nepomnyaschiy, Tatiana V. Avramenko, Aleksandr A. Karabtsov, Vladimir V. Ivanov, Victor P. Bulgakov, Sergey V. Gnedenkov, Yury N. Kulchin, Yury N. Zhuravlev
Agrobacterium tumefaciens carrying pPZP-RCS2-nptII, pPZP-RCS2-nptII/LoSilA1, pPZP-RCS2-nptII/LoSilA1-EGFP and pPZP-RCS2-nptII/EGFP plasmids were used to inoculate leaf discs of sterile, clonally cultivated plantlets of N. tabacum L. (cv Xanthi) according to the previously described conditions [42]. Leaf discs were co-cultivated with A. tumefaciens for 48 h and transferred to the WB/A agarized medium supplemented with 0.5 mg/L 6-benzylaminopurine and 2.0 mg/L α-naphthaleneacetic acid [43] containing 500 mg/L cefotaxime and 100 mg/L kanamycin. Transgenic callus cultures expressing the selectable marker (nptII) gene alone or together with the LoSilA1 gene, LoSilA1-EGFP fusion gene or EGFP gene, namely Nt-cV, Nt-cS, Nt-cSG and Nt-cG, were obtained after four months of selection with kanamycin. Plant regeneration was achieved by placing the 4–5 week-old primary calli on hormone-free W medium containing 100 mg/L kanamycin under a 16/8 h light/dark cycle. Thus, transgenic plantlets expressing the selectable marker (nptII) gene alone or together with the LoSilA1 gene, LoSilA1-EGFP fusion gene or EGFP gene, namely Nt-pV, Nt-pS, Nt-pSG and Nt-pG, were obtained. The control non-transformed callus culture and plants were established from the same plantlets and cultivated under the same conditions as the transformed ones.
Enzyme-instructed self-assembly of the stereoisomers of pentapeptides to form biocompatible supramolecular hydrogels
Published in Journal of Drug Targeting, 2020
Adrianna N. Shy, Jie Li, Junfeng Shi, Ning Zhou, Bing Xu
As shown in Scheme 1, the stereoisomers are based on a known EISA substrate that has the sequences of Nap-L-Phe-L-Phe-Gly-L-Glu-L-pTyr (Nap-FFGEpY, 1-P). According to the previous report, [41] after dephosphorylation, 1-P becomes 1, which self-assembles in water to form nanofibres. The entanglement of the nanofibres results in a hydrogel. In the structure of 1-P, Nap-FF acts as an excellent self-assembly motif [42] due to its ability to provide multiple aromatic–aromatic interactions and hydrogen bonds, and tyrosine phosphate (Yp) renders the precursor to be a substrate of alkaline phosphatase. Moreover, a previous study reported the use of kinase/phosphatase to regulate the supramolecular hydrogel formed by cell compatible hydrogelator 1 [41]. Despite that, 1-P has illustrated the development of EISA for generating supramolecular hydrogels, 1 is susceptible to proteolysis catalysed by proteases, thus its applications is limited. To increase the stability of the precursors and hydrogelators, one approach is to introduce D-amino acid into 1-P or 1. Thus, this work aims to generate a series of stereoisomers of 1 and to examine the properties of the stereoisomers. According to the structure of 1-P, replacing L-Phe by D-Phe generates 2-P, exchanging L-Glu and L-Tyr to D-Glu and D-Tyr produces 3-P, and converting all the L-amino acid residues in 1-P to D-amino acid residues leads to 4-P. In such a design, it is expected 2-P, 3-P and 4-P act as the precursors for hydrogelators 2, 3, and 4, respectively. Based on the synthetic procedure used to make 1-P, solid-phase peptide synthesis (SPPS) was used to produce 2-P, 3-P, and 4-P. Briefly, the protected phosphotyrosine (Fmoc-pTyr (D or L-enantiomer)) was added to 2-chlorotrityl chloride resin. After capping any open sites on the resin, 20% piperidine was then added to deprotect the amino acid. After several washes with dimethylformamide, the Fmoc protected amino acids Glu, Gly, and Phe (D or L-enantiomers) were subsequently added followed by deprotection with 20% piperidine and several washes between each addition of the amino acid. The peptide was capped with 2-naphthaleneacetic acid and cleaved from the resin with trifluoroacetic acid (TFA), creating the peptides shown in Scheme 1. The same general procedure was used for producing the hydrogelator peptides (1, 2, 3, and 4).