A Novel ‘Gene Insertion/Marker Out’ (GIMO) Method for Transgene Expression and Gene Complementation in Rodent Malaria Parasites

Research on the biology of malaria parasites has greatly benefited from the application of reverse genetic technologies, in particular through the analysis of gene deletion mutants and studies on transgenic parasites that express heterologous or mutated proteins. However, transfection in Plasmodium is limited by the paucity of drug-selectable markers that hampers subsequent genetic modification of the same mutant. We report the development of a novel ‘gene insertion/marker out’ (GIMO) method for two rodent malaria parasites, which uses negative selection to rapidly generate transgenic mutants ready for subsequent modifications. We have created reference mother lines for both P. berghei ANKA and P. yoelii 17XNL that serve as recipient parasites for GIMO-transfection. Compared to existing protocols GIMO-transfection greatly simplifies and speeds up the generation of mutants expressing heterologous proteins, free of drug-resistance genes, and requires far fewer laboratory animals. In addition we demonstrate that GIMO-transfection is also a simple and fast method for genetic complementation of mutants with a gene deletion or mutation. The implementation of GIMO-transfection procedures should greatly enhance Plasmodium reverse-genetic research

On misunderstanding Heraclitus: The justice of organisation structure

Writers on organisational change often refer to the cosmology of Heraclitus in their work. Some use these references to support arguments for the constancy and universality of organisational change and the consignment to history of organisational continuity and stability. These writers misunderstand the scope of what Heraclitus said. Other writers focus exclusively on the idea that originated with Heraclitus that the universe is composed of processes and not of things. This idea, which has been particularly associated with Heraclitus’s thought from the time of Plato, does indeed provide a rich source of insights into organisational analysis, not least the current trends towards giving proper attention to processual studies of organisational change. Yet there is some uncertainty as to whether Heraclitus actually said that the universe was composed exclusively of processes rather than things, and even if that was what he thought, he intended his ideas on flux to be understood not in isolation but in the context of other aspects of his cosmology. Writers on organisational change seldom make reference to this wider context. Heraclitus was a rational but also a religious thinker. A central element in his thought was the notion of divine Justice, which to a Greek of his era meant the order of the universe. Remote as his Olympian theology may seem today, it sets a crucial and entirely rational context for understanding his ideas about flux. It means that ideas about continuity and stability were quite as important in Heraclitus’s cosmology as his more commonly quoted ideas about change. This paper sets out an overview of Heraclitus’s philosophy, insofar as it appears to have potential relevance to organisational analysis, and discusses how far it supports or contradicts the ideas that organisational change scholars have drawn from it

A Global Characterization and Identification of Multifunctional Enzymes

Multi-functional enzymes are enzymes that perform multiple physiological functions. Characterization and identification of multi-functional enzymes are critical for communication and cooperation between different functions and pathways within a complex cellular system or between cells. In present study, we collected literature-reported 6,799 multi-functional enzymes and systematically characterized them in structural, functional, and evolutionary aspects. It was found that four physiochemical properties, that is, charge, polarizability, hydrophobicity, and solvent accessibility, are important for characterization of multi-functional enzymes. Accordingly, a combinational model of support vector machine and random forest model was constructed, based on which 6,956 potential novel multi-functional enzymes were successfully identified from the ENZYME database. Moreover, it was observed that multi-functional enzymes are non-evenly distributed in species, and that Bacteria have relatively more multi-functional enzymes than Archaebacteria and Eukaryota. Comparative analysis indicated that the multi-functional enzymes experienced a fluctuation of gene gain and loss during the evolution from S. cerevisiae to H. sapiens. Further pathway analyses indicated that a majority of multi-functional enzymes were well preserved in catalyzing several essential cellular processes, for example, metabolisms of carbohydrates, nucleotides, and amino acids. What’s more, a database of known multi-functional enzymes and a server for novel multi-functional enzyme prediction were also constructed for free access at http://bioinf.xmu.edu.cn/databases/MFEs/index.htm

Association between CYP19 gene SNP rs2414096 Polymorphism and polycystic ovary syndrome in Chinese women

<p>Abstract</p> <p>Background</p> <p>Several studies have reported the association of the SNP rs2414096 in the CYP19 gene with hyperandrogenism, which is one of the clinical manifestations of polycystic ovary syndrome (PCOS). These studies suggest that SNP rs2414096 may be involved in the etiopathogenisis of PCOS. To investigate whetherthe CYP19 gene SNP rs2414096 polymorphism is associated with the susceptibility to PCOS, we designed a case-controlled association study including 684 individuals.</p> <p>Methods</p> <p>A case-controlled association study including 684 individuals (386 PCOS patients and 298 controls) was performed to assess the association of SNP rs2414096 with PCOS. Genotyping of SNP rs2414096 was conducted by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method that was performed on genomic DNA isolated from blood leucocytes. Results were analyzed in respect to clinical test results.</p> <p>Results</p> <p>The genotypic distributions of rs2414096 (GG, AG, AA) in the CYP19 gene (GG, AG, AA) in women with PCOS (0.363, 0.474, 0.163, respectively) were significantly different from that in controls (0.242, 0.500, 0.258, respectively) (<it>P </it>= 0.001). E2/T was different between the AA and GG genotypes. Age at menarche (AAM) and FSH were also significantly different among the GG, AG, and AA genotypes in women with PCOS (P = 0.0391 and 0.0118, respectively). No differences were observed in body mass index (BMI) and other serum hormone concentrations among the three genotypes, either in the PCOS patients or controls.</p> <p>Conclusions</p> <p>Our data suggest that SNP rs2414096 in the CYP19 gene is associated with susceptibility to PCOS.</p

Optimisation of the conditions for stripping voltammetric analysis at liquid-liquid interfaces supported at micropore arrays: a computational simulation

Micropore membranes have been used to form arrays of micro interfaces between immiscible electroly tesolutions (μITIES) as a basis for the sensing of non-redoxactiveions. Implementation of stripping voltammetry as asensing method at these arrays of μITIES was applied recently to detect drugs and biomolecules at low concentrations. The present study uses computational simulation to investigate the optimum conditions for stripping voltammetricsensing at the μITIES array. In this scenario, thediffusion of ions in both the aqueous and the organic phasescontributes to the sensing response. The influence of the preconcentration time, the micropore aspect ratio, the location of the micro interface within the pore, the ratio of the diffusion coefficients of the analyte ion in the organic and aqueous phases, and the pore wall angle were investigated. The simulations reveal that the accessibility of the microinterfaces during the preconcentration period should not be hampered by a recessed interface and that diffusional transport in the phase where the analyte ions are preconcentrated should be minimized. This will ensure that the ions are accumulated within the micropores close to the interface and thus be readily available for back transferduring the stripping process. On the basis of the results, an optimal combination of the examined parameters is proposed,which together improve the stripping voltammetric signal and provide an improvement in the detection limit

A review of elliptical and disc galaxy structure, and modern scaling laws

A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their models to describe the radial distribution of stars in `nebulae'. This article reviews the progress since then, providing both an historical perspective and a contemporary review of the stellar structure of bulges, discs and elliptical galaxies. The quantification of galaxy nuclei, such as central mass deficits and excess nuclear light, plus the structure of dark matter halos and cD galaxy envelopes, are discussed. Issues pertaining to spiral galaxies including dust, bulge-to-disc ratios, bulgeless galaxies, bars and the identification of pseudobulges are also reviewed. An array of modern scaling relations involving sizes, luminosities, surface brightnesses and stellar concentrations are presented, many of which are shown to be curved. These 'redshift zero' relations not only quantify the behavior and nature of galaxies in the Universe today, but are the modern benchmark for evolutionary studies of galaxies, whether based on observations, N-body-simulations or semi-analytical modelling. For example, it is shown that some of the recently discovered compact elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to appear in "Planets, Stars and Stellar Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references incl. many somewhat forgotten, pioneer papers. Original submission to Springer: 07-June-201

Analysis of Microsatellite Polymorphism in Inbred Knockout Mice

Previously, we found that the genotype of 42 out of 198 mouse microsatellite loci, which are distributed among all chromosomes except the Y chromosome, changed from monomorphism to polymorphism (CMP) in a genetically modified inbred mouse strain. In this study, we further examined whether CMP also relates to the homologous recombination in gene knockout (KO) mouse strains. The same 42 microsatellite loci were analyzed by polymerase chain reaction (PCR) in 29 KO inbred mouse strains via short tandem sequence repeat (STR) scanning and direct sequence cloning to justify microsatellite polymorphisms. The C57BL/6J and 129 mouse strains, from which these 29 KO mice were derived, were chosen as the background controls. The results indicated that 10 out of 42 (23.8%) loci showed CMP in some of these mouse strains. Except for the trinucleotide repeat locus of D3Mit22, which had microsatellite CMP in strain number 9, the core sequences of the remaining 41 loci were dinucleotide repeats, and 9 out of 41 (21.95%) showed CMPs among detected mouse strains. However, 11 out of 29 (37.9%) KO mice strains were recognized as having CMPs. The popular dinucleotide motifs in CMP were (TG)n (50%, 2/4), followed by (GT)n (27.27%, 3/11) and (CA)n (23.08%, 3/13). The microsatellite CMP in (CT)n and (AG)n repeats were 20% (1/5). According to cloning sequencing results, 6 KO mouse strains showed insertions of nucleotides whereas 1 showed a deletion. Furthermore, 2 loci (D13Mit3 and D14Mit102) revealed CMP in 2 strains, and mouse strain number 9 showed CMPs in two loci (D3Mit22 and D13Mit3) simultaneously. Collectively, these results indicated that microsatellite polymorphisms were present in the examined inbred KO mice

Influence of Ketotifen, Cromolyn Sodium, and Compound 48/80 on the survival rates after intestinal ischemia reperfusion injury in rats

<p>Abstract</p> <p>Background</p> <p>Mast cells were associated with intestinal ischemia-reperfusion injury, the study was to observe the influence of Ketotifen, Cromolyn Sdium(CS), and Compound 48/80(CP) on the survival rates on the third day after intestinal ischemia-reperfusion injury in rats.</p> <p>Methods</p> <p>120 healthy Sprague-Dawley rats were randomly divided into 5 groups, Sham-operated group (group S), model group (group M), group K, group C and group CP. Intestinal damage was triggered by clamping the superior mesenteric artery for 75 minutes, group K, C, and CP were treated with kotifen 1 mg·kg^-1, CS 50 mg·kg^-1, and CP 0.75 mg·kg^-1i.v. at 5 min before reperfusion and once daily for three days following reperfusion respectively. Survival rate in each group was recorded during the three days after reperfusion. All the surviving rats were killed for determining the concentration of serum glutamic-oxaloacetic transaminase(AST), glutamic pyruvic transaminase(ALT), the ratio of AST compare ALT(S/L), total protein(TP), albumin(ALB), globulin(GLB), the ratio of ALB compare GLB(A/G), phosphocreatine kinase(CK), lactate dehydrogenase(LDH), urea nitrogen(BUN) and creatinine(CRE) at the 3^rdday after reperfusion. And ultrastructure of IMMC, Chiu's score, lung histology, IMMC counts, the levels of TNF-α, IL-1β, IL-6 and IL-10 of the small intestine were detected at the same time.</p> <p>Results</p> <p>Intestinal ischemia-reperfusion injury reduced the survival rate. The concentrations of TP, ALB and level of IL-10 in intestine in group M decreased significantly while the concentrations of S/L, LDH and the levels of IL-6 and TNF-α in intestine increased significantly compared with group S (<it>P </it>< 0.05). Treatment with Ketotifen and CS increased the survival rate compared with group M (<it>P </it>< 0.05), attenuated the down-regulation or up-regulation of the above index (<it>P </it>< 0.05). Treatment with CP decreased the survival rate on the 3^rdday after reperfusion compared with group M(<it>P </it>< 0.05). Group K and C had better morphology in IMMC in the small intestine and in the lungs than in group M and CP, although the Chiu's score and IMMC counts remained the same in the five groups(<it>P </it>> 0.05).</p> <p>Conclusion</p> <p>Mast cell inhibition after ischemia prior to reperfusion and following reperfusion may decrease the multi-organ injury induced by intestine ischemia reperfusion, and increase the survival rates.</p

Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche.

Age at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition