Exploring the antimalarial potential of the methoxy-thiazinoquinone scaffold: Identification of a new lead candidate

A small library of antiplasmodial methoxy-thiazinoquinones, rationally designed on the model of the previously identified hit 1, has been prepared by a simple and inexpensive procedure. The synthetic derivatives have been subjected to in vitro pharmacological screening, including antiplasmodial and toxicity assays. These studies afforded a new lead candidate, compound 9, endowed with higher antiplasmodial potency compared to 1, a good selectivity index when tested against a panel of mammalian cells, no toxicity against RBCs, a synergistic antiplasmodial action in combination with dihydroartemisinin, and a promising inhibitory activity on stage V gametocyte growth. Computational studies provided useful insights into the structural requirements needed for the antiplasmodial activity of thiazinoquinone compounds and on their putative mechanism of action.     

Syntax manipulation changes perception of mobbing call sequences across passerine species

Many species approach predators to harass them and drive them away. Both the intensity of this antipredator strategy and its success are positively related to the size of the group that carries out this mobbing. To recruit individuals to the mob, members of prey species produce mobbing calls. In some songbirds—the Japanese tit, Parus minor, and the southern pied babbler, Turdoides bicolor—mobbing calls are structurally complex and it has been suggested that they convey information by means of compositional syntax, when meaningful items are combined into larger units. These two species combine alert and recruitment calls into an alert and recruitment sequence when attracting conspecifics to cooperate in mobbing a predator. Whether this rudimentary, two‐call, compositional structure is used by other bird species in mobbing calls and how it can alter the ability of heterospecifics to adequately recognize mobbing calls is not well understood. Heterospecifics’ responses to mobs are critical to the success of the mobbing strategy, so it is of great importance to understand whether and how syntax influences these responses. To address these questions, we conducted two playback experiments. Firstly, we investigated whether the great tit, Parus major, extracts different meanings from different individual motifs (i.e., component calls), and from combined motifs in both natural and artificially reversed order. We found that great tits extract different meanings from the two motifs involved in mobbing calls and that they also discriminate for motif order reversal in the mobbing call sequence. Secondly, we investigated whether heterospecifics (the coal tit, Periparus ater, and the common chaffinch, Fringilla coelebs) are sensitive to syntax alteration of great tit mobbing calls. While chaffinches did not respond to great tit mobbing calls, coal tits were sensitive to mobbing call sequence reversal although they did not react in the same way as conspecific subjects. Overall, whereas our results indicate that tits are sensitive to call reversal, this is not to say that tits actually use compositional syntax to increase the information content.     

Development of 28 EST‐SSR markers based on transcriptome sequences of Gobiobotia filifer and cross‐species amplification

Gobiobotia filifer is a small benthic fish distributed in Yangtze River Basin. The abundance of G. filifer increased after impoundment of Xiluodu Dam and Xiangjiaba Dam. The state of population structure and changes of genetic diversity before and after impoundment of Xiluodu Dam and Xiangjiaba Dam were interesting issues. However, efficient molecular markers were rare, which will limit us to solve above problems. Twenty‐eight expressed sequence tag SSRs (EST‐SSRs) were successfully identified and verified as stable amplification and polymorphic loci by polyacrylamide gel electrophoresis (PAGE) and capillary electrophoresis. The number of alleles at these EST‐SSR loci ranged from 3 to 14, the polymorphism information content values were 0.125–0.897, and the observed and expected heterozygosities were 0.0–0.857 and 0.132–0.928, respectively. Cross‐species amplification of the 28 loci developed in this study was examined in seven individuals of each of the 7 taxa. The amplification efficiency of 28 EST‐SSRs primer pairs is related to the distance of genetic relationship between cross‐species with G. filifer, and same subfamily species (Xenophysogobio boulengeri and Xenophysogobio nudicorpa) showed the highest (50%) amplification efficiency. These EST‐SSR markers could be used to analyse genetic diversity and population structure of G. filifer and related species.     

Genetic analysis of stunted growth by nuclear-cytoplasmic interaction in interspecific hybrids of Capsicum by using RAPD markers

When eight cultivars of Capsicum annuum were used as female parents in interspecific crosses with two accessions of C. chinense, dwarfism occurred in hybrids originating from 10 out of 16 combinations, while hybrids of the remaining 6 combinations grew normally. In contrast, when C. chinense was used as female parent, all of the hybrids showed severely stunted growth as if affected by a virus. These results suggested that the stunted growth expressed in the cross of C. chinense x C. annuum is caused by an interaction between nuclear gene(s) from C. annuum and the cytoplasm of C. chinense. To examine the number of nuclear gene(s) which cause(s) the stunted growth, we backcrossed F₁ hybrids of C. annuum x C. chinense to C. chinense. About one-quarter of the progeny in the backcrossed hybrids of C. chinense x (C. annuum x C. chinense) showed the same stunted growth shown by the f₁ hybrids of C. chinense x C. annuum, suggesting that two complementary genes of C. annuum cause the stunted growth. However, the higher abortion rates of ovules and lower germination percentage of seeds in C. chinense x C. annuum than in the selfed C. chinense implied that the genetic ratio of the stunted type would have been higher than that observed in the C. chinense x (C. annuum x C. chinense) progeny. We then attempted a linkage analysis between the stunted growth and randomly amplified polymorphic DNA (RAPD) of C. chinense x (C. annuum x C. chinense) progeny. A RAPD marker that associated with 94% of the stunted plants but not with 94% of the normal one was identified. This confirmed that a single nuclear gene of C. annuum which is linked to the RAPD marker with a recombination value of 6% causes the stunted growth in an interaction with the cytoplasm of C. chinense.     

Host preference of a temperate mistletoe: Disproportional infection on three co‐occurring host species influenced by differential success

The mistletoe Tristerix verticillatus (Loranthaceae) parasitizes within a small area of the Yerba Loca Nature Sanctuary near Santiago, Chile, three co‐occurring hosts: Schinus montanus (Anacardiaceae), Fabiana imbricata (Solanaceae) and Berberis montana (Berberidaceae). Previous studies suggest that T. verticillatus may be favoured when parasitizing S. montanus relative to the other two host species. We hypothesize that infection of S. montanus is not proportional to its local abundance or appearance, that S. montanus is more intensively parasitized than other available hosts, and that host provenance is a determinant of the fate of the infecting seed. We compare the incidence of infection of T. verticillatus in relation to local availability and appearance variables, and the intensity of infection of T. verticillatus, on the three co‐occurring host species. We then test the effects of host provenance on mistletoe seed establishment success with a seed cross inoculation experiment varying the donor and receptor hosts. Finally, we test whether there are differences in establishment success between manually processed seeds and seeds defecated by the avian disperser Mimus thenca (Passeriformes: Mimidae). Our results show that the three hosts have an aggregated spatial distribution. Schinus montanus was parasitized at a higher rate than expected by its local availability and appearance, and inoculated seeds showed differential development depending on the origin of the seeds: seeds from T. verticillatus parasitizing S. montanus inoculated to S. montanus twigs showed higher germination and lower mortality than seeds from T. verticillatus parasitizing F. imbricata inoculated to S. montanus twigs. Furthermore, seeds defecated by the avian disperser, M. thenca, had higher adherence and reduced mortality when compared to manually processed seeds. The disproportional host infection found is discussed in terms of the differential establishment of mistletoe seeds, morphological characteristics of hosts and the behaviour of dispersing birds.     

深化微生物检验教学改革, 培养学生综合能力

《微生物检验》是医学检验技术专业重要的专业核心课程, 具有很强的实践性和操作性。课程采取“校企合作”的方法, 根据医院人才培养标准整合教学内容, 在教学过程中强调工学结合, 积极采用个案分析等多种教学方法和手段, 开拓学生思路, 养成良好的科学态度。通过“实训-见习-实习”等实践环节, 培养学生的动手能力, 以及分析问题、解决问题的能力, 为临床输送“医学检验技能应用型人才”。     

Monitoring the stability of crosslinked protein crystals biotemplates: a feasibility study

Protein crystals, routinely prepared for the elucidation of protein 3D structures by X-ray crystallography, present an ordered and highly accurate 3D array of protein molecules. Inherent to the 3D arrangement of the protein molecules in the crystal is a complementary 3D array of voids made of interconnected cavities and exhibiting highly ordered porosity. The permeability of the porosity of chemically crosslinked enzyme protein crystals to low molecular weight solutes, was used for enzyme mediated organic synthesis and size exclusion chromatography. This permeability might be extended to explore new potential applications for protein crystals, for example, their use as bio-templates for the fabrication of novel, nano-structured composite materials. The quality of composites obtained from "filling" of the ordered voids in protein crystals and their potential applications will be strongly dependent upon an accurate preservation of the order in the original protein crystal 3D array during the "filling" process. Here we propose and demonstrate the feasibility of monitoring the changes in 3D order of the protein array by a step-by-step molecular level monitoring of a model system for hydrogel bio-templating by glutaraldehyde crosslinked lysozyme crystals. This monitoring is based on step-by-step comparative analysis of data obtained from (i) X-ray crystallography: resolution, unit cell dimensions and B-factor values and (ii) fluorescence decay kinetics of ultra-fast laser activated dye, impregnated within these crystals. Our results demonstrated feasibility of the proposed monitoring approach and confirmed that the stabilized protein crystal template retained its 3D structure throughout the process.     

Isolation and characterization of polymorphic microsatellite loci from RAPD product in half-smooth tongue sole (Cynoglossus semilaevis) and a test of cross-species amplification

Eleven polymorphic microsatellite loci have been isolated and characterized from random amplified polymorphic DNA product in half-smooth tongue sole, Cynoglossus semilaevis. Twenty-one microsatellites were selected for designing microsatellite primers, of which 11 gave working primer pairs. They had between three and 12 alleles. Observed and expected heterozygosities varied from 0.53 to 0.93, and from 0.52 to 0.80, respectively. Five additional fish species assessed for cross-species amplification revealed between one and three positive amplifications and between zero and three polymorphic loci per species.