A comparative binding study of modified bovine immunodeficiency virus TAR RNA against its TAT peptide

Besides generating novel binding peptides or small molecules to their RNA target, successful design of chemically modified RNA constructs capable of tighter binding with their binding peptides is also of significant importance. Herein, the synthesis and binding studies of a series of both wt and mutant bovine immunodeficiency virus (BIV) TAR RNA constructs against its Tat peptide are reported. Understanding the requirements that enable RNA construct binding properties, especially at the hairpin loop or internal bulge, would afford potential therapeutic approaches to control the BIV life cycle.     

Stereoselective synthesis and anti-inflammatory activities of 6- and 7-membered dioxacycloalkanes

A class of 5-trifluoroacetylamino-1,3-dioxacycloalkanes, 5-benzoylamino-1,3-dioxacycloalkanes, and 5-amino-1,3-dioxacycloalkane compounds were stereoselectively synthesized as potential anti-inflammatory drug candidates. The anti-inflammatory activities of these compounds were tested using the xylene-induced mouse ear edema model, from which multiple compounds possessing anti-inflammatory properties which surpass aspirin were identified; these compounds were then compared to establish structure-activity relationships.     

Toward the development of chemoprevention agents (III): synthesis and anti-inflammatory activities of a new class of 5-glycylamino-2-substituted-phenyl-1,3-dioxacycloalkanes

A new series of 5-glycylamino-2-substituted-phenyl-1,3-dioxacycloalkanes were designed and synthesized. The anti-inflammatory activities of these compounds were tested using the xylene-induced mouse ear edema model. Sixteen of these new compounds exhibited comparable or better anti-inflammatory activities than aspirin suggesting that they can be further developed as potential anti-inflammatory drug leads. In addition, treatment with these anti-inflammatory agents did not prolong tail bleeding time in mice. The structure/activity relationships were also analyzed among these compounds. Considering their good efficacy and safety profiles, some 5-glycylamino-2-substituted-phenyl-1,3-dioxacycloalkanes are worthy to be explored further in assessing the possible link between anti-inflammation and cancer prevention.     

油菜双单倍体诱导育种技术研究进展

油菜是食用油、优质饲料蛋白的重要来源,杂种优势利用是油菜培育优势性状最重要的手段,且提高亲本的选育效率对优质品种的培育具有积极的推动作用。现有油菜育种技术存在效率低、周期长、盲目性大、应用范围有限等诸多问题,不适于油菜产业快速发展的需求。双单倍体诱导育种技术是近年来新兴的一种快速选育油菜新品种的技术方法。该技术以操作简便、应用范围广、效率高等优势被广泛应用于油菜新品种的选育过程中。从油菜双单倍体诱导技术创新研究的发现、作用表现、诱导机制、作用价值等方面系统地综述了油菜双单倍体诱导技术的研究进展,展望了油菜双单倍体诱导技术的应用前景,以期为未来油菜双单倍体诱导技术以及其他作物诱导系的研究和利用提供参考。     

Seasonal plasticity of duodenal morphology and histology in Passer montanus

When facing seasonal environmental changes, flying birds and small mammals may develop adaptive gastrointestinal changes to optimize their digestive and absorptive strategies to meet the changing of physiologic needs. As a main component of gastrointestinal tract, small intestine is extraordinarily sensitive to food abundance, food quality, and other environmental factors. However, the detailed morphological adaptations of the small intestine during seasonal changes are largely unknown. Here, we studied the morphological and histological dynamics of duodenum from Passer montanus in Zhalong Nature Reserve in China during seasonal changes. The luminal and wall cross-section area were greater in spring and autumn than that in summer. Villus height and width went up to peak values in winter and showed similar seasonal dynamic changes with that of mucosal thickness, while villus atrophy accompanied by the deepest crypt depth was easily detected in summer. Epithelium thickness was coincident with villus atrophy except a sharp increase in summer. Submucosal thickness was negatively correlated with that of mucosa, while the size, but not total number, of duodenal glands was altered to reflect to seasonal changes. Neither the inner circular nor the outer longitudinal muscle showed seasonal morphological changes, indicating the relatively stable plasticity of intestine muscle structures. Taken together, we propose that phenotypic flexibility in digestive morphology and histology enables small birds to cope with remarkable seasonal changes.     

Novel synthesis and anti-inflammatory activities of 2,5-disubstituted-dioxacycloalkanes

A novel stereospecific synthetic route to obtain a series of 2,5-disubstituted-dioxacycloalkanes is reported. Using an in vivo inhibition assay by monitoring xylene-induced ear edema in mice, the structure-activity relationship of the dioxacycloalkane compounds was studied, and compounds possessing high anti-inflammatory activity were identified.     

Synthesis and cytotoxic activities of beta-carboline amino acid ester conjugates

Beta-carboline represents a class of compounds with potent anti-tumor activity by intercalating with DNA. To further enhance the cytotoxic potency and bioavailability of beta-carboline, a series of novel beta-carboline amino acid ester conjugates were designed and synthesized, and the cytotoxic activities of these compounds were tested using a panel of human tumor cell lines. In addition, the membrane permeability of these compounds was evaluated in vitro using a Caco-2 cell monolayer model. The beta-carboline amino acid ester conjugates demonstrated improved cytotoxic activity compared to the parental beta-carbolines. In particular, the Lys/Arg conjugates were the most potent analogs with an IC(50) value of 4 and 1 microM against human cervical carcinoma cells. The low interaction energy of Arg conjugate based on molecular modeling may contribute to its enhanced cytotoxicity. Taken together, this study provided new insights into structure-activity relationships in the beta-carboline amino acid ester conjugates and identified the beta-carboline Lys/Arg conjugates as promising lead compounds for further in vivo biological and molecular evaluation.     

Dual-acting agents that possess free radical scavenging and antithrombotic activities: design, synthesis, and evaluation of phenolic tetrahydro-beta-carboline RGD peptide conjugates

A new approach to construct a single dual-acting agent is described. Compounds 6a-c are potent free radical scavengers as demonstrated by the EC(50) values in PC12 cell survival assay in term of NO, H(2)O(2), and ()OH scavenging activity. The Ach-induced vaso-relaxation assay further confirms the potent NO scavenging activity of compounds 6a-c. In addition, 6a-c are efficacious in a rat arterial thrombosis, and are active in ADP- or PAF-induced in vitro platelet aggregation assay, suggesting that compounds 6a-c also possess anti-thrombotic activities. Since both free radical and thrombogenesis are important risk factors in myocardial ischemic/reperfusion injuries, these dual-acting agents having both free radical scavenging and antithrombolic activities may potentially be beneficial toward their treatment.