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991.
Budi?WinartoEmail author F.?Rachmawati Jaime?A.?Teixeira da SilvaEmail author 《Plant Growth Regulation》2011,65(3):513-529
A successful protocol for high frequency callus induction and plant regeneration from Anthurium andreanum Linden ex André cv. Tropical half-anthers is described. Different variables using Winarto and Teixeira and Murashige and
Skoog basal media supplemented with several plant growth regulators [2,4-dichlorophenoxy acetic acid (0.1–1.0 mg/l), α-naphthalene
acetic acid (0.01–0.2 mg/l), thidiazuron (0.5–2.0 mg/l), 6-benzylaminopurine (0.5–1.0 mg/l), and kinetin (0.5–1.0 mg/l)] were
tested for their ability to induce high frequency callusing in half-anthers, indirect regeneration and rooting of shoots.
Basal medium, as well as the combination and concentration of hormones applied, had a significant effect on callus formation,
shoot regeneration and adventitious root formation. Winarto and Teixeira-1, an original basal medium containing 0.01 mg/l
α-naphthalene acetic acid, 0.5 mg/l thidiazuron and 1.0 mg/l 6-benzylaminopurine was suitable for callus formation while an
improved basal medium i.e., New Winarto–Teixeira-3 supplemented with 0.25 mg/l 2,4-dichlorophenoxy acetic acid, 0.02 mg/l
α-naphthalene acetic acid, 1.5 mg/l thidiazuron and 0.75 mg/l 6-benzylaminopurine enhanced callus formation. High shoot regeneration
and multiplication was also possible on New Winarto–Teixeira-3. Shoots formed a strong adventitious root system on New Winarto–Teixeira-3
containing 0.2 mg/l α-naphthalene acetic acid and 1.0 mg/l kinetin. Plantlets that varied in size and performance were successfully
acclimatized and adapted to ex vitro conditions. Cytological analysis of 180 acclimatized-plantlets ex vitro revealed that
34 were haploid (n = 14–18), 15 aneuploid (n = 20–26), 126 diploid (n = 28–34) and 5 triploid (n = 45–57). The potential use of this protocol for developing half-anther culture of other Anthurium species or cultivars is discussed. 相似文献
992.
A microspore culture protocol for Brassica oleracea of Indonesian origin (cv. ‘Kemeh’) has been successfully established. A high number of embryos formed with high microspore
density i.e. 15 × 104 cells/ml. Embryo formation was improved by using flower buds (4.5–4.6 mm in length) as explants, a temperature treatment
at 30.5°C for 48 h and then transfer to 25°C continuously until embryos formed. A total of 295 embryos were obtained from
189 buds, 30% of which were abnormal (i.e. with an abnormal cotyledon or lacking hypocotyls). All normal embryos that grew
and survived, 165 in total, were successfully transferred to soil and grew well in plastic bags (15 cm in diameter) containing
a mixture of burned-rice husk and organic manure (1:1, v/v). 相似文献
993.
Despite the major interest in membrane proteins at functional, genomic, and therapeutic levels, their biochemical and structural
study remains challenging, as they require, among other things, solubilization in detergent micelles. The complexity of this
task derives from the dependence of membrane protein structure on their anisotropic environment, influenced by a delicate
balance between many different physicochemical properties. To study such properties in a small protein–detergent complex,
we used fluorescence measurements and molecular dynamics (MD) simulations on the transmembrane part of glycophorin A (GpAtm)
solubilized in micelles of dihexanoylphosphatidylcholine (DHPC) detergent. Fluorescence measurements show that DHPC has limited
ability to solubilize the peptide, while MD provides a possible molecular explanation for this. We observe that the detergent
molecules are balanced between two different types of interactions: cohesive interactions between detergent molecules that
hold the micelle together, and adhesive interactions with the peptide. While the cohesive interactions are detergent mediated,
the adhesion to the peptide depends on the specific interactions between the hydrophobic parts of the detergent and the topography
of the peptide dictated by the amino acids. The balance between these two parameters results in a certain frustration of the
system and rather slow equilibration. These observations suggest how molecular properties of detergents could influence membrane
protein stabilization and solubilization. 相似文献
994.
Rivas EI Driver JP Garabatos N Presa M Mora C Rodriguez F Serreze DV Stratmann T 《Journal of immunology (Baltimore, Md. : 1950)》2011,186(7):4078-4087
CD4 T cells are crucial effectors in the pathology of type 1 diabetes (T1D). Successful therapeutic interventions for prevention and cure of T1D in humans are still elusive. Recent research efforts have focused on the manipulation of T cells by treatment with DNA. In this paper, we studied the effects of a DNA treatment strategy designed to target antigenic peptides to the lysosomal compartment on a monospecific T cell population termed 2.5mi(+) T cells that shares reactivity with the diabetogenic T cell clone BDC-2.5 in the NOD mouse. MHC class II tetramer analysis showed that repeated administrations were necessary to expand 2.5mi(+) T cells in vivo. This expansion was independent of Ag presentation by B cells. A single peptide epitope was sufficient to induce protection against T1D, which was not due to Ag-specific T cell anergy. Typical Th2 cytokines such as IL-10 or IL-4 were undetectable in 2.5mi(+) T cells, arguing against a mechanism of immune deviation. Instead, the expanded 2.5mi(+) T cell population produced IFN-γ similar to 2.5mi(+) T cells from naive mice. Protection against T1D by DNA treatment was completely lost in NOD.CD28(-/-) mice which are largely deficient of natural regulatory T cells (Treg). Although Ag-specific Foxp3(+) Treg did not expand in response to DNA treatment, diabetes onset was delayed in Treg-reconstituted and DNA-treated NOD.SCID mice. These observations provide evidence for a Treg-mediated protective mechanism that is independent of the expansion or de novo generation of Ag-specific Treg. 相似文献
995.
Elva I. Cort��s-Guti��rrez Martha I. D��vila-Rodr��guez Jos�� Lu��s Fern��ndez Carmen L��pez-Fern��ndez Altea Gos��lbez Jaime Gos��lvez 《The journal of histochemistry and cytochemistry》2011,59(7):655-660
The comet assay is a well-established, simple, versatile, visual, rapid, and sensitive tool used extensively to assess DNA damage and DNA repair quantitatively and qualitatively in single cells. The comet assay is most frequently used to analyze white blood cells or lymphocytes in human biomonitoring studies, although other cell types have been examined, including buccal, nasal, epithelial, and placental cells and even spermatozoa. This study was conducted to design a protocol that can be used to generate comets in subnuclear units, such as chromosomes. The new technique is based on the chromosome isolation protocols currently used for whole chromosome mounting in electron microscopy, coupled to the alkaline variant of the comet assay, to detect DNA damage. The results show that migrant DNA fragments can be visualized in whole nuclei and isolated chromosomes and that they exhibit patterns of DNA migration that depend on the level of DNA damage produced. This protocol has great potential for the highly reproducible study of DNA damage and repair in specific chromosomal domains. 相似文献
996.
Newell EW Ely LK Kruse AC Reay PA Rodriguez SN Lin AE Kuhns MS Garcia KC Davis MM 《Journal of immunology (Baltimore, Md. : 1950)》2011,186(10):5823-5832
T cells specific for the cytochrome c Ag are widely used to investigate many aspects of TCR specificity and interactions with peptide-MHC, but structural information has long been elusive. In this study, we present structures for the well-studied 2B4 TCR, as well as a naturally occurring variant of the 5c.c7 TCR, 226, which is cross-reactive with more than half of possible substitutions at all three TCR-sensitive residues on the peptide Ag. These structures alone and in complex with peptide-MHC ligands allow us to reassess many prior mutagenesis results. In addition, the structure of 226 bound to one peptide variant, p5E, shows major changes in the CDR3 contacts compared with wild-type, yet the TCR V-region contacts with MHC are conserved. These and other data illustrate the ability of TCRs to accommodate large variations in CDR3 structure and peptide contacts within the constraints of highly conserved TCR-MHC interactions. 相似文献
997.
Alfaro C Perez-Gracia JL Suarez N Rodriguez J Fernandez de Sanmamed M Sangro B Martin-Algarra S Calvo A Redrado M Agliano A Gonzalez A Rodriguez I Bolaños E Hervás-Stubbs S Perez-Calvo J Benito A Peñuelas I Vigil C Richter J Martinez-Forero I Melero I 《Journal of immunology (Baltimore, Md. : 1950)》2011,187(11):6130-6142
Twenty-four patients with metastatic cancer received two cycles of four daily immunizations with monocyte-derived dendritic cells (DC). DC were incubated with preheated autologous tumor lysate and subsequently with IFN-α, TNF-α, and polyinosinic:polycytidylic acid to attain type 1 maturation. One DC dose was delivered intranodally, under ultrasound control, and the rest intradermally in the opposite thigh. Cyclophosphamide (day -7), GM-CSF (days 1-4), and pegIFN alpha-2a (days 1 and 8) completed each treatment cycle. Pretreatment with cyclophosphamide decreased regulatory T cells to levels observed in healthy subjects both in terms of percentage and in absolute counts in peripheral blood. Treatment induced sustained elevations of IL-12 in serum that correlated with the output of IL-12p70 from cultured DC from each individual. NK activity in peripheral blood was increased and also correlated with the serum concentration of IL-12p70 in each patient. Circulating endothelial cells decreased in 17 of 18 patients, and circulating tumor cells markedly dropped in 6 of 19 cases. IFN-γ-ELISPOT responses to DC plus tumor lysate were observed in 4 of 11 evaluated cases. Tracing DC migration with [(111)In] scintigraphy showed that intranodal injections reached deeper lymphatic chains in 61% of patients, whereas with intradermal injections a small fraction of injected DC was almost constantly shown to reach draining inguinal lymph nodes. Five patients experienced disease stabilization, but no objective responses were documented. This combinatorial immunotherapy strategy is safe and feasible, and its immunobiological effects suggest potential activity in patients with minimal residual disease. A randomized trial exploring this hypothesis is currently ongoing. 相似文献
998.
Varicella-zoster virus (VZV) reactivation causes herpes zoster, which is accompanied by an influx of lymphocytes into affected ganglia, but the stimulus for this infiltrate is not known. We report that VZV infection of ganglia leads to increased CXCL10 production in vitro, in an explant ganglion model and in naturally infected dorsal root ganglia (DRG) during herpes zoster. Lymphocytes expressing the receptor for CXCL10, CXCR3, were also observed throughout naturally infected ganglia during herpes zoster, including immediately adjacent to neurons. This study identifies VZV-induced CXCL10 as a potential driver of T lymphocyte recruitment into DRG during herpes zoster. 相似文献
999.
1000.
Transgenic expression of the RNA-dependent RNA polymerase 3D(pol) inhibited infection of Theiler's murine encephalitis virus (TMEV), a picornavirus from which it was derived. Here, we infected 3D(pol) transgenic mice with another picornavirus, as well as an alphaherpesvirus and a rhabdovirus. 3D(pol) transgenic FVB mice had significantly lower viral loads and survived longer after infection with all three types of viruses than nontransgenic FVB mice. Viral inhibition among three different types of virus by transgenic 3D(pol) suggests that the mechanism of action is not the direct interference with picornaviral 3D(pol) but instead may be the changing of host cells to an antiviral state before or after viral infection occurs, as basal interferon levels were higher in 3D(pol) transgenic mice before infection. Further study of this mechanism may open new possibilities for future antiviral therapy. 相似文献