Plant regeneration of Iris pallida Lam. and Iris germanica L. via somatic embryogenesis from leaves,apices and young flowers

Irones are violet-scented ketonic compounds contained in the rhizome of certain species of iris. As cultivation of the iris tends to decrease, a selection program has been initiated to find the best performing clones in terms of growth and yield. Parallel to this selection, in vitro regeneration studies have been carried out in order to multiply interesting clones. A method of rapid multiplication by somatic embryogenesis associated with multibudding was developed. Callus was obtained from leaf bases, flower pieces or rhizome apices; the best explants were flower pieces. The induction media used to obtain embryogenic callus were Murashige & Skoog (1962) media. Assays with adding of proline in these media have showed that it could double the yield of embryogenic callus. The embryogenic expression medium was the Knudson's orchid agar (Knudson 1946) medium. Conformity of the plants obtained was checked by comparing their chemotypes with those of the mother plants.Abbreviations AIB indolyl butyric acid - BAP 6-benzylaminopurine - Kin 6-furfurylaminopurine - KN Knudson's orchid Agar - MS Murashige & Skoog medium - NAA naphthaleneacetic acid - N6 Chu et al. medium - Pro proline - 2,4-D dichlorophenoxyacetic acid     

Atrial Tachyarrhythmia in Rgs5-Null Mice

Aims

The aim of this study was to elucidate the effects of regulator of G-protein signaling 5 (Rgs5), a negative regulator of G protein-mediated signaling, on atrial repolarization and tachyarrhythmia (ATA) in mice.

Methods and Results

In present study, the incidence of ATA were increased in Rgs5^−/− Langendorff-perfused mouse hearts during program electrical stimulation (PES) (46.7%, 7 of 15) and burst pacing (26.7%, 4 of 15) compared with wild-type (WT) mice (PES: 7.1%,1 of 14; burst:7.1%,1 of 14) (P<0.05). And the duration of ATA also shown longer in Rgs5^−/− heart than that in WT, 2 out of 15 hearts exhibited sustained ATA (>30 s) but none of them observed in WT mice. Atrial prolonged repolarization was observed in Rgs5^−/− hearts including widened P wave in surface ECG recording, increased action potential duration (APD) and atrial effective refractory periods (AERP), all of them showed significant difference with WT mice (P<0.05). At the cellular level, whole-cell patch clamp recorded markedly decreased densities of repolarizing K⁺ currents including I_Kur (at +60 mV: 14.0±2.2 pF/pA) and I_to (at +60 mV: 16.7±1.3 pA/pF) in Rgs5^−/− atrial cardiomyocytes, compared to those of WT mice (at +60 mV I_to: 20.4±2.0 pA/pF; I_kur: 17.9±2.0 pF/pA) (P<0.05).

Conclusion

These results suggest that Rgs5 is an important regulator of arrhythmogenesis in the mouse atrium and that the enhanced susceptibility to atrial tachyarrhythmias in Rgs5^−/− mice may contribute to abnormalities of atrial repolarization.     

Palynological investigations on some Hypericum taxa (Hypericaceae) growing naturally in Turkey

This study examined the detailed pollen morphological structures of sixteen Hypericum taxa (four endemic, twelve non endemic) including eight sections showing the natural distribution in Turkey: H. sect. Ascyreia (H. calycinum L.), H. sect. Heterophyllum (H. heterophyllum Vent.), H. Sect. Taeniocarpium (Hypericum confertum Choisy subsp. confertum, H. venustum Fenzl, H. linaroides Bosse), H. sect. Drosocarpium (H. montbretii Spach, H. bithynicum Boiss.), H. sect. Crossophyllum (H. adenotrichum Spach, H. orientale L.), H. sect. Olympia (H. olympicum L. subsp. olympicum), H. sect. Origanifolia (H. origanifolium Willd., H. avicularifolium Jaub and Spach subsp. depilatum (Freyn and Bornm.) Robson var. depilatum, H. avicularifolium Jaub. and Spach subsp. byzantinum) and H. sect. Hypericum (H. tetrapterum Fries, H. perforatum L., H. triquetrifolium Tura). These taxa were studied under light microscope and scanning electron microscope for the first time. Of the taxa studied, H. tetrapterum has the smallest pollen grains (on average 15.85–17.20 × 15.45–16.05 μm); and H. olympicum subsp. olympicum the largest grains (on average 22.90–23.10 × 21.40–22.10 μm). The pollen grains of 15 taxa are subprolate and one taxon is prolate-spheroidal. The regular pollen grains of all 16 taxa are 3-zonocolporate. Ornamentation is microreticulate; lumina regularly spaced in eight taxa, tectum perforatum; tectal perforations regularly spaced in seven taxa and tectum perforatum; and tectal perforations grouped together in one taxon. Endoaperture is cruciform porus, with short lateral and meridional extensions in ten taxa, cruciform porus, transversally elongated, with very small lateral extensions in one taxon and lalongate colpus in five taxa. Basic pollen types are ten taxa in type X, five taxa in type IV and one taxon in type II.     

膜联蛋白AnxB1序列缺失突变体的结构模建及活性分析

为获得低分子量、低免疫原性的膜联蛋白AnxB1的序列缺失突变体 ,以AnxB1C端的 4个内部同源结构域为基础 ,模拟构建了 4个突变体群 .利用同源模建的方法对各突变体进行结构模建和分子优化 ,最后选择 4个结构最为合理的突变体在大肠杆菌GST融合表达系统中表达 .结果显示 :GST M3和GST M4均表达出较强的抗凝血活性 ,且免疫原性也降低为原来的 1 2 ,为进一步构建兼具抗凝、溶栓双重功能的靶向性溶栓药物奠定了基础 .     

Biomechanical Study on the Novel Biomimetic Hemi-Pelvis Prosthesis

A pelvic endoprosthesis is the primary means of pelvic reconstruction after internal hemipelvectomy. In this study, a novel biomimetic hemipelvic prosthesis, including an artificial ilium, an artificial acetabulum, and an artificial pubis, was developed. A Finite Element Method （FEM） was carried out to investigate the biomechanical performance of a pelvis reconstructed with biomimetic hemipelvic prosthesis. Two models, including the reconstructed pelvis and the original pelvis （control model）, were established according to the geometry from CT data of a human male patient with pelvic bone sarcomas. The FE models predict that the biomeehanical function of the pelvic ring can be reestablished using this prosthesis. Results show that the body force loaded on the S 1 vertebra is restored and transferred towards the sacro-iliac joint, and along the ilium onto the bearing surface of the artificial ilium, then to the artificial acetabulum and pubis. Von Mises stresses observed in this reconstructed pelvis model are still within a low and elastic range below the yielding strength of cortical bone and Ti6A14V. The values of deformation and strain of the reconstructed pelvis are close to the data obtained in the original pelvis. With the partial replacement of the pubis, little influence is found towards the pubis symphysis. However, the interface between the prosthesis and pelvic bone may become the critical part of the reconstructed pelvis due to the discontinuity in the material properties, which results in stress shielding and deformation constraining. So a biomimetic flexible connection or inter layer to release the deformation of pelvis is suggested in future designing.     

广州市水环境中喹诺酮类抗生素的污染特征

采用固相萃取-高效液相色谱法(HPLC),分析了4种喹诺酮类抗生素在广州市水环境(珠江、污水厂、湖泊和自来水)中的污染特征.结果显示,珠江广州河段(出广州市)和污水厂喹诺酮类抗生素污染严重,最高含量达349 ng·L-1,珠江水样中大部分抗生素含量明显高于瑞士河流中药物含量,污水厂(出水)中抗生素含量比国外污水厂(出水)含量水平高.受城市污水和养殖业废水污染的影响,广州市不同区域的自来水也受到一定程度抗生素药物污染,含量在O～231 ng·L-1水平.仅在一个区域的水样中,有较低含量的喹诺酮类抗生素检出.城市污水和河流周边养殖废水的排放成为水环境中抗生素污染的重要来源之一.     

Molecular characterization,heterologous expression and resistance analysis of OsLEA3-1 from Oryza sativa

Late embryogenesis abundant (LEA) proteins in organisms are closely associated with resistance to abiotic stresses. Here we characterized a rice LEA protein, OsLEA3-1, by bioinformatics analysis and heterologous expression in Escherichia coli. Bioinformatics analysis showed that OsLEA3-1 contains a 603-bp open reading frame encoding a putative polypeptide of 200 amino acids, which contains a “LEA_4” motif at positions 5–48 and belongs to a typical group 3 LEA. OsLEA3-1 polypeptide is rich in Ala, Lys, and Thr, but depleted in Cys, Pro, and Trp residues; and is strongly hydrophilic. Secondary structure prediction showed that OsLEA3-1 polypeptide contained an α-helical domain in positions 4-195 but not any β-sheet domain. OsLEA3-1 gene can express in shoot and root of germinating seeds, seedling, panicles, mature embryo, seed, and callus; and was also up-regulated by ultraviolet (UV), heat, cold, salt, and emergency drought. OsLEA3-1 gene was introduced into E. coli. A fusion protein of about 28.03 kDa was expressed in recombinant E. coli cells after the induction by isopropylthio-β-D-galactoside. Compared with control E. coli cells harbouring pET30a, the accumulation of the OsLEA3-1 fusion protein increased the tolerance of the E. coli recombinants under diverse abiotic stresses: high salinity, metal ions, hyperosmotic, heat, and UV radiation. The OsLEA3-1 has the ability to protect the lactate dehydrogenase activity under heating, drying, and MnCl₂ treatment in vitro. The findings suggested that the OsLEA3-1 gene may contribute to the ability of adapting to stressful environments of plants.