Stimulation of the Mu A protein-mediated strand cleavage reaction by the Mu B protein, and the requirement of DNA nicking for stable type 1 transpososome formation. In vitro transposition characteristics of mini-Mu plasmids carrying terminal base pair mutations.

We have examined the effects of a T----C point mutation at the terminal nucleotide of the Mu ends in a mini-Mu plasmid on the early steps in the in vitro transposition reaction. These mutations inhibit the introduction of nicks at the Mu ends in a reaction with Mu A, HU, and integration host factor proteins. The presence of the point mutation at either the left end or the right end is sufficient to block the nicking reaction at both ends, indicating that the reaction is normally concerted. Addition of Mu B and ATP, however, dramatically stimulates the reaction of mutant mini-Mu plasmids carrying the mutation at one end but not at both ends. The data suggest that the Mu B protein mediates its effect through direct interaction with Mu A and that Mu B may play a role in an earlier step in the transposition process than previously proposed. In the presence of Mu B, two products are observed with the left end or right end mutant mini-Mu plasmids, a normal protein-DNA intermediate (Type 1 complex) which contains nicks at both Mu ends and an abortive product composed of free relaxed plasmid which is nicked only at the wild-type end. Furthermore, stable protein-DNA complexes characteristic of the first step in the in vitro transposition reaction are not observed in the absence of nicking or when only one end is a nicked; the introduction of nicks at both Mu ends is a prerequisite for stable transpososome assembly.     

Evolutionary origins of Brassicaceae specific genes in Arabidopsis thaliana

Background  

All sequenced genomes contain a proportion of lineage-specific genes, which exhibit no sequence similarity to any genes outside the lineage. Despite their prevalence, the origins and functions of most lineage-specific genes remain largely unknown. As more genomes are sequenced opportunities for understanding evolutionary origins and functions of lineage-specific genes are increasing.     

The Expression and Activity of Cathepsins D,H and K in Asthmatic Airways

Tumstatin is an anti-angiogenic collagen IV α3 fragment, levels of which are reduced in the airways of asthmatics. Its reduction may be due to the degradation by extracellular matrix (ECM) proteases. Cathepsins play a role in ECM remodelling, with cathepsin D, H and K (CTSD, CTSH and CTSK) being associated with lung diseases. CTSD modulates the NC1 domains of collagen molecules including tumstatin, while CTSH and CTSK are involved in ECM degradation. The role of these cathepsins in the regulation of tumstatin in the lung has not previously been examined. We demonstrated that CTSB, D, F, H, K, L and S mRNA was expressed in the airways. Quantification of immunohistochemistry showed that there is no difference in the global expression of CTSD, CTSH and CTSK between asthmatics and non-asthmatics. CTSD and CTSK, but not CTSH had the capacity to degrade tumstatin. No difference was observed in the activity of CTSD and H in bronchoalveolar lavage fluid of asthmatic and non-asthmatics, while CTSK was undetectable. This indicates that while CTSD possesses the potential to directly regulate tumstatin, and thus angiogenesis through this mechanism however, it is not likely to be involved in the dysregulation of tumstatin found in asthmatic airways.     

Evolution of anaerobic ciliates from the gastrointestinal tract: phylogenetic analysis of the ribosomal repeat from Nyctotherus ovalis and its relatives

The 18S and 5.8S rDNA genes and the internal transcribed spacers ITS-1 and ITS-2 of ciliates living in the hindgut of frogs, millipedes, and cockroaches were analyzed in order to study the evolution of intestinal protists. All ciliates studied here belong to the genus Nycrotherus. Phylogenetic analysis revealed that these ciliates from a monophyletic group that includes the distantly related anaerobic free-living heterotrichous ciliates Metopus palaeformis and Metopus contortus. The intestinal ciliates from the different vertebrate and invertebrate hosts are clearly divergent at the level of their rDNA repeats. This argues for the antiquity of the associations and a predominantly vertical transmission. This mode of transmission seems to be controlled primarily by the behavior of the host. The different degrees of divergence between ciliates living in different strains of one and the same cockroach species most likely reflect the different geographical origins of the hosts. In addition, host switches must have occurred during the evolution of cockroaches, since identical ciliates were found only in distantly related hosts. These phenomena prevent the reconstruction of potential cospeciation events.      

Use of vector control to protect people from sleeping sickness in the focus of Bonon (Côte d’Ivoire)

BackgroundGambian human African trypanosomiasis (gHAT) is a neglected tropical disease caused by Trypanosoma brucei gambiense transmitted by tsetse flies (Glossina). In Côte d’Ivoire, Bonon is the most important focus of gHAT, with 325 cases diagnosed from 2000 to 2015 and efforts against gHAT have relied largely on mass screening and treatment of human cases. We assessed whether the addition of tsetse control by deploying Tiny Targets offers benefit to sole reliance on the screen-and-treat strategy.Methodology and principal findingsIn 2015, we performed a census of the human population of the Bonon focus, followed by an exhaustive entomological survey at 278 sites. After a public sensitization campaign, ~2000 Tiny Targets were deployed across an area of 130 km² in February of 2016, deployment was repeated annually in the same month of 2017 and 2018. The intervention’s impact on tsetse was evaluated using a network of 30 traps which were operated for 48 hours at three-month intervals from March 2016 to December 2018. A second comprehensive entomological survey was performed in December 2018 with traps deployed at 274 of the sites used in 2015. Sub-samples of tsetse were dissected and examined microscopically for presence of trypanosomes. The census recorded 26,697 inhabitants residing in 331 settlements. Prior to the deployment of targets, the mean catch of tsetse from the 30 monitoring traps was 12.75 tsetse/trap (5.047–32.203, 95%CI), i.e. 6.4 tsetse/trap/day. Following the deployment of Tiny Targets, mean catches ranged between 0.06 (0.016–0.260, 95%CI) and 0.55 (0.166–1.794, 95%CI) tsetse/trap, i.e. 0.03–0.28 tsetse/trap/day. During the final extensive survey performed in December 2018, 52 tsetse were caught compared to 1,909 in 2015, with 11.6% (5/43) and 23.1% (101/437) infected with Trypanosoma respectively.ConclusionsThe annual deployment of Tiny Targets in the gHAT focus of Bonon reduced the density of Glossina palpalis palpalis by >95%. Tiny Targets offer a powerful addition to current strategies towards eliminating gHAT from Côte d’Ivoire.     

Is inosine the physiological energy source of pig erythrocytes?

Pig erythrocytes are unable to metabolize glucose and their physiological energy source is unknown. These cells have a high-capacity nucleoside transport system with similar properties to that responsible for nucleoside transport in other species. Nucleoside transport is sufficiently rapid to allow the possibility that inosine and/or adenosine may represent major energy substrates for pig erythrocytes in vivo. Normal and adenosine deaminase-deficient pig erythrocytes have similar ATP levels, suggesting that adenosine is not important in this respect. However, it was calculated that an extracellular inosine concentration of only 40 nM could support the cells' entire energy requirement, a value 40-fold lower than plasma levels of this nucleoside.     

Ghrelin在小鼠体内早期胚胎发育中的表达

为了探讨Ghrelin是否在昆明系小白鼠(Mus musculus)体内早期胚胎发育中发挥作用。运用激素超排卵技术及动物解剖学方法获取小鼠体内不同发育阶段的早期胚胎,应用实时定量PCR技术检测了Ghrelin mRNA的相对表达量。结果表明,Ghrelin mRNA在小鼠各期胚胎中均有表达;同时,GhrelinmRNA的表达量呈现一定规律性变化,2-细胞期表达量最低,8-细胞期表达量达到最高值,总体趋势是先降低后升高之后又降低。研究结果揭示,Ghrelin可能在小鼠早期胚胎发育中发挥一定的作用。     

The identification of 17 -hydroxy-17-methyl-1,4-androstadien-3-one as a metabolite of the anabolic steroid drug 17 -hydroxy-17-methyl-1,4-androstadien-3-one in man

The more polar of the two major urinary metabolites of methandrostenolone, 17β-hydroxy-17-methyl-1,4-androstadien-3-one, in man has already been identified as 6β-hydroxymethandrostenolone, 6β, 17β-dihydroxy-17-methyl-1,4-androstadien-3-one. The other metabolite has now been identified as the 17-epimer of methandrostenolone, 17α-hydroxy-17-methyl-1,4-androstadien-3-one. The compound was isolated from the freely extractable neutral fraction of urine following the administration of 5 mg of the drug to normal men. The relevant chromatographic fractions from thin layer and gas liquid systems were identified by carbon skeleton chromatography. The 17-epimer has been synthesised, details of which are included, and the previously unidentified metabolite was found to be identical with the synthetic compound.