Effect of phytohormones on plant regeneration from callus ofGladiolus cultivar “Jenny Lee”

Summary Callus capable of plant regeneration was initiated at a higher frequency from the basal leaves of in vitro plants (70% explants) as compared to cormel slices (30% explants) when cultured on medium containing various concentrations of auxin. The greatest number of plants were regenerated from 4-mo.-old callus (112 plants/g fresh weight callus) cultured on medium containing 10 mg/liter (53.8μM) 1-napthaleneacetic acid. The addition of 2 mg/liter (9.3μM) kinetin to a Murashige and Skoog’s basal salts regeneration medium resulted in an average two- to three-fold increase in the number of plants regenerated compared to regeneration on medium without hormones. Ten months after callus initiation, all callus maintained on auxin-supplemented media showed a drastic reduction in its capacity to regenerate plants. Ten-month-old callus maintained on dicamba regenerated the greatest number of plants (14 to 23 plants regenerated per gram fresh weight callus) as compared to callus maintained 10 mo. on medium containing 1-napthaleneacetic acid or 2,4-dichlorophenoxyacetic acid. Cormel slices cultured on cytokinin-supplemented media formed small amounts of callus which regenerated up to 19 plants per cormel slice within 1 to 2 mo. after the cormel slice had been placed on either 10 mg/liter (49.2μM) N⁶-2-isopentenyladenosine or 1 mg/liter (4.4μM) 6-benzylaminopurine.     

NaCl and TDZ are Two Key Factors for the Improvement of In Vitro Regeneration Rate of Salicornia europaea L.

The present study aimed to find out suitable conditions for the In vitro culture of Sallcornla europaea L. and to develop an efficient regeneration system. S. europaea plants were regenerated successfully In vitro from callus derived from mature embryos. Via the method of 2,4-dlchlorophenoxyacetlc acid （2,4-D）-short-treatment on mature seeds, callus was Induced from hypocotyls on the MS medium with 4.55 μmol/L N-phenyl-N＇-1, 2, 3-thladlazol-5-yl urea （TDZ） 3-4 weeks after the seeds germinated. The callus differentiated Into shoots at a rate of 27.6% after subculture for one time on the same medium. When NaCl was Included In the medium, shoots were formed In cluster and the shoot differentiation frequency was Increased to 55.2%. The shoots were rooted when cultured on 1/2 MS medium supplemented with Indole-3-butyric acid （IBA）, kinetin （KN） end activated charcoal （AC）. The results Indicated that NeCl and TDZ played an Important role In the Improvement of the regeneration rate of the halophyte, S. europaea.     

Plant regeneration from cultured protoplasts of a glutinous rice

Young embryos of rice (Oryza sativa L. subsp, japonicavar. Guo-xiang No. 1) were cultured on MS agar medium(2,4-D 2 mg/l). Calli were formed and subcultured on N6 agar medium (2,4-D 2 mg/l ). After selection, the small, grainy and pale yellowish cell clusters with dense cytoplasm were used in protoplast preparation. Isolated protoplasts were cultured in N6 medium (2,4-D 1 mg/l, 6-BA 0.2 mg/l)~1 with agarose block culture method. The protoplasts grew, divided and formed calli. After inducing differentiation, the regenerated mature plants were obtained.     

‘章姬'草莓茎段愈伤组织诱导及高频植株再生体系的建立北大核心CSCD

In order to cultivate an improved variety with higher potential yield and establish an efficient in vitro regeneration system of strawberry ‘Akihim'(Fragaria × ananassa), callus induction and plant regeneration protocol was designed for solve browning problem. A formal L9(34)orthogonal experiment was designed to investigate the browning research in primary culture using explants of creeping stems excised from aseptic seedlings. Based on the improved medium above, single-factor experiments were conducted to select effective plant growth regulators and appropriate concentrations on blank MS medium. A L9(34)orthogonal experiment was designed to study effects of types and concentrations of plant growth regulators on callus induction, adventitious shoot formation, and plant regeneration. The results indicated that MS medium was inferior to B5 and 1/2MS in inhibiting browning condition. The browning rate was dramatically reduced while the callus still survived on the medium with the addition of 20 g·L-1 Na2S2O3. The callus induction and shoot formation of the explants were observed on MS + 0.1 mg· L-1 6-BA + 0.05 mg·L-1 2, 4-D + 0.1 mg·L-1 NAA with effective inhibiting browning. The optimal medium protocol for multiple shoots proliferation was MS + 0.1 mg·L-1 6-BA + 0.1 mg·L-1 NAA where the proliferation coefficient was 12.86 after 30 d. Healthily regenerated plants were yielded on culture medium 1/2MS + 1.0 g·L-1 AC after 35 d, with a rooting rate of 92.50%. More than 95% of plantlets survived after transplanting into field. The rapid propagation system is helpful to provide homogeneous progeny and high quality seedlings for cultivation of strawberry ‘Akihime' as well as a technical reference for other strawberry species in vitro regeneration. [ABSTRACT FROM AUTHOR]     

Genetic transformation of gentian using wild-type Agrobacterium rhizogenes

Leaf sections of greenhouse-grown Miscanthus x ogiformis Honda 'Giganteus' plants and leaf sections or shoot apices of in vitro shoot cultures were grown on Murashige and Skoog medium containing various concentrations of benzyladenine (BA) and 2,4-dichlorophenoxyacetic acid. On leaf sections, the callus induction decreased with increasing BA concentration. The percentage of embryogenic callus was increased, the percentage of root-forming callus decreased, and a new shoot-forming callus type was formed by inclusion of BA during callus induction. A higher percentage of shoot-forming callus was formed on shoot apices compared with leaf sections of in vitro-grown shoots when cultured on 0.4 μM BA. The largest number of plants per callus piece was regenerated from shoot-forming callus, but maintenance of the high regeneration capacity proved difficult. This revised version was published online in June 2006 with corrections to the Cover Date.     

Protein changes associated with plant regeneration in embryogenic calli of sugarcane (Saccharum sp.).

Plant regeneration from cultured immature inflorescence segments (3–5 mm) of sugarcane (Saccharum sp) var. CP 5243 was obtained via somatic embryogenesis. Embryogenic callus culture was initiated on MS medium supplemented with 2,4-D (13.5 μM) over 30 days. The callus was subcultured every 15–20 days on MS medium supplemented with 2,4-D (4.5 μM), arginine (50 mg l^-1) and proline (500 mg l^-1). The callus was subjected to five treatments: 2,4-D (4.5 μM), Picloram (8.2 μM) and Dicamba (22.6 μM). SPC was determined at the beginning, after 20 days in culture, and every 24 hours thereafter up to 72 hours. SDS-PAGE electrophoresis was performed based on soluble protein content. Some differences were found between SPC and bands (intensity and number) for all treatments associated with shoot formation. The results point out the association of soluble protein content and callus regenerative ability of sugarcane cv. CP5243 and suggest the presence of a marker protein (between 55–70 kDa) for embryogenic callus regeneration ability in this cultivar. This revised version was published online in June 2006 with corrections to the Cover Date.     

甘蓝型油菜叶柄原生质体培养再生植株

Two cultivars of Brassica napus,Altex and Canadian twins,were used as materials.Protoplasts isolated from petioles of plants grown in vitro were cultured in Nitsch mediumsupplemented with 0.5mg/L BA,0.5mg/L NAA,1mg/L 2,4-D,100mg/L serine,800mg/Lglutamine,4% sucrose and 0.4mol/L mannitol.After 2 days of culture,the first division wasobserved.The division frequency estimated after 10 days of culture was 30—60%.One weekafter transferring onto MS medium containing 6mg/L GA_3 and 3mg/L BA,protoplast-derivedcalli regenerated into shoots.The regeneration frequency of the two cultivars was 24% and31% respectively.It was found that the protoplasts isolated from petioles could float on thesurface of the 3% sucrose contained solution which was very favourable both to purificationand culture of the protoplasts.     

In vitro culture of Ginkgo

Summary Ginkgo biloba L. is an important landscape tree, is resistant to insect, fungi and other pests, and produces a number of chemicals that have pharmaceutical properties (termed ginkgolides). Studies were initiated to establish an in vitro culture protocol for Ginkgo. Explants (intact embryos, embryos with cotyledons removed, and cotyledon tissue) were removed from disinfested seeds and cultured on Murashige and Skoog minimal organics medium with various combinations of either 2,4-dichlorophenoxyacetic acid (2,4-D) or naphthaleneacetic acid (NAA) and either kinetin or benzyladenine (BA). Cultures were incubated in the light and morphological development was recorded. Both embryo and cotyledon explants produced callus (cotyledon tissue produced the most callus). Ginkgolides A and B were detected in callus tissue extracts. Intact embryo cultures initiated on media with 2,4-D plus NAA for 5 wk produced shoots and roots when transferred to media with 4.5 μM 2,4-D alone for an additional 5 wk. Plants were transferred from the 2,4-D media to pots and maintained in the greenhouse.     

Plant regeneration via somatic embryogenesis in many cultivars of cotton (Gossypium hirsutum L.)

Summary Embryogenic callus was formed from several cultivars of cotton (Gossypium hirsutum L.) when sections of hypocotyl and cotyledon were cultured on medium supplemented with 5 mg/liter 6-(γ, γ-dimethylallyl-amino)-purine (2iP) and 0.1 mg/liter α-naphthaleneacetic acid (NAA) for callus initiation and proliferation, and subcultured on medium supplemented with 5 mg/liter NAA and 0.1 to 1 mg/liter 2iP for embryogenic callus induction. It seems that a high 2iP:auxin ratio is preferred for callus initiation and proliferation, but should be exchanged with a higher NAA:cytokinin ratio before differentiation will occur. Embryogenic calluses were recovered at a frequency of 2 to 85% depending on the cultivar used. Coker cultivars produced embryogenic callus faster and at higher frequencies than other cultivars. Embryogenic callus produced somatic embryos on phytohormone-free medium. This medium was used to maintain and proliferate embryogenic callus for a perid of 18 to 24 mo. Somatic embryos were converted to plants on a lower ionic strength medium supplemented with 0.1 mg/liter gibberellic acid (GA₃) and 0.01 mg/liter NAA. Glucose was the only carbohydrate used through all phases of tissue culture and was much better than sucrose, on which phenolic production was very high. High temperature (30° C) and low light intensity (9 μE · m⁻² · s⁻¹) were optimal conditions for callus initiation, embryogenic callus induction, and maintenance, whereas lower temperature (25° C) and high light intensity (90 μE · m⁻² s⁻¹) were the optimal conditions for somatic embryo maturation, germination, and plantlet development. Plants could be regenerated within 10 to 12 wk in Cokers or 7 to 8 mo. in others.     

Plant regeneration from cultured protoplasts of a glutinous rics

Young embryos of ricy (Oryza sativa L.subsp.japonica var.Guo-xiang No.1) were cultured on MS agar medium(2,4-D 2 mg/l).Calli were formed and subcultured on N6 agar medium (2,4-D 2 mg/l).After selection,the small,grainy and pale yellowish cell clusters with dense cytoplasm were used in protoplast preparation. Isolated protoplasts were cultured in N6 medium (2,4-D 1 mg/l,6-BA 0.2 mg/l)^1* with agarose block culture method.The protoplasts grew,divided and formed calli.After inducing differentiation,the regenerated mature plants were obtained.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.