The effects of γ-irradiation on the priming by deoxyribonucleohistone of ribonucleic acid polymerase

1. The effect of gamma-irradiation of solutions of DNA and deoxyribonucleohistone (DNH) on their ability to prime the synthesis of RNA by DNA-dependent RNA polymerase has been studied. 2. The priming ability of both DNA and DNH decreased continuously with increasing radiation dose, but more rapidly with DNH. 3. These decreases have been compared with decreases in molecular weight and with the breakdown of the specific hydrogen-bonded structure of DNA. 4. It is concluded that a process was occurring during gamma-irradiation of DNH that, although involving a decrease in molecular weight, did not diminish and even enhanced its priming ability. This is consistent with previous physicochemical evidence that gamma-irradiation causes dissociation of histone from DNH.     

The Structure of the Gene Pools of the Ethnic Populations of Altai–Sayan Region Based on of Mitochondrial DNA Polymorphism Data

Using the data on mitochondrial DNA (mtDNA) polymorphism, genetic structures of the four Turkic-speaking ethnic groups of Altai–Sayan highlands, Southern Altaians (Altai- Kizhi), Khakassians, Shorians, and Sojots, were described. Mitochondrial gene pools of the populations examined were characterized by different ratios between Mongoloid (M*, C, D, E, G, A, B, and F) and Caucasoid (H, U, T, J, and K) mtDNA lineages. All the populations studied had a strongly pronounced Mongoloid component, the frequency of which was 88.2% in Sojots, 75.9% in Khakassians, 67.4% in Altaians, and 64.3% in Shorians. Maximum frequency of the Caucasoid component (35.7%) was observed in Shorians. Phylogenetic and statistical analyses of the mtDNA group frequency distribution patterns in the gene pools of the ethnic populations of Altai–Sayan highlands and the adjacent territories showed that the populations of the region fell into three groups. The first group included Khakassians, Tuvinians and Altaians, the second group consisted of Sojots, Buryats, and Mongols, while the third group was composed of Uigurs, Kazakhs, and Kyrgyzes. The isolated position of Shorians among the populations examined can be explained by their different anthropological composition and their presumptive relatedness to Finno-Ugric populations of Siberia.     

Evaluating the Phylogenetic Position of Chinese Tree Shrew （Tupaia belangeri chinensis） Based on Complete Mitochondrial Genome： Implication for Using Tree Shrew as an Alternative Experimental Animal to Primates in Biomedical Research

Tree shrew(Tupaia belangeri) is currently placed in Order Scandentia and has a wide distribution in Southeast Asia and Southwest China.Due to its unique characteristics,such as small body size,high brain-to-body mass ratio,short reproductive cycle and life span,and low-cost of maintenance,tree shrew has been proposed to be an alternative experimental animal to primates in biomedical research.However,there are some debates regarding the exact phylogenetic affinity of tree shrew to primates.In this study,we determined the mtDNA entire genomes of three Chinese tree shrews(T.belangeri chinensis) and one Malayan flying lemur(Galeopterus variegatus).Combined with the published data for species in Euarchonta,we intended to discern the phylogenetic relationship among representative species of Dermoptera,Scandentia and Primates.The mtDNA genomes of Chinese tree shrews and Malayan flying lemur shared similar gene organization and structure with those of other mammals.Phylogenetic analysis based on 12 concatenated mitochondrial proteinencoding genes revealed a closer relationship between species of Scandentia and Glires,whereas species of Dermoptera were clustered with Primates.This pattern was consistent with previously reported phylogeny based on mtDNA data,but differed from the one reconstructed on the basis of nuclear genes.Our result suggested that the matrilineal affinity of tree shrew to primates may not be as close as we had thought.The ongoing project for sequencing the entire genome of Chinese tree shrew will provide more information to clarify this important issue.     

The enhancement of the oral bioavailability of γ-tocotrienol in mice by γ-cyclodextrin inclusion

Cyclodextrin (CD) is widely used in the pharmaceutical and nutritional fields to form an inclusion complex with lipophilic compounds for the improvement of their aqueous solubility, stability and diffusibility under physiological conditions. In this study, we investigated the effect of the γ-tocotrienol (γT3) inclusion complex with CD on its oral bioavailability. Five-week-old C57BL6 mice were fed a vitamin E-free diet for 28 days, followed by the oral administration of 2.79 mg of γT3-rich fraction (TRF) extracted from rice bran or the equivalent dose (14.5 mg) of a CD inclusion complex with TRF (TRF/CD). The levels of γT3 in sequentially collected plasma were determined by LC-MS/MS. The pharmacokinetic study revealed that the plasma concentrations of γT3 were increased and peaked at 6 or 3 h after the oral administration of TRF or TRF/CD, respectively (C_max values of 7.9±3.3 or 11.4±4.5 μM, respectively). The area under the curve of plasma γT3 concentration also showed a 1.4-fold increase in the group administered with TRF/CD compared with the TRF-only group. Furthermore, the mice that had received the TRF/CD tended to reduce the endotoxin shock induced by injection with lethal amounts of Escherichia coli lipopolysaccharide, compared with the mice that had received TRF alone. Taken together, our results suggest that the CD inclusion improved γT3 bioavailability, resulting in the enhancement of γT3 physiological activity, which would be a useful approach for the nutrition delivery system.     

The Molecular Symplesiomorphies Shared by the Stem Groups of Metazoan Evolution: Can Sites as Few as 1 % Have a Significant Impact on Recognizing the Phylogenetic Position of Myzostomida?

Although it is clear that taxon sampling, alignments, gene sampling, tree reconstruction methods and the total length of the sequences used are critical to the reconstruction of evolutionary history, weakly supported or misleading nodes exist in phylogenetic studies with no obvious flaw in those aspects. The phylogenetic studies focusing on the basal part of bilaterian evolution are such a case. During the past decade, Myzostomida has appeared in the basal part of Bilateria in several phylogenetic studies of Metazoa. However, most researchers have entertained only two competing hypotheses about the position of Myzostomida—an affinity with Annelida and an affinity with Platyhelminthes. In this study, dozens of symplesiomorphies were discovered by means of ancestral state reconstruction in the complete 18S and 28S rDNAs shared by the stem groups of Metazoa. By contrastive analysis on the datasets with or without such symplesiomorphic sites, we discovered that Myzostomida and other basal groups are basal lineages of Bilateria due to the corresponding symplesiomorphies shared with earlier lineages. As such, symplesiomorphies account for approximately 1–2 % of the whole dataset have an essential impact on phylogenetic inference, and this study reminds molecular systematists of the importance of carrying out ancestral state reconstruction at each site in sequence-based phylogenetic studies. In addition, reasons should be explored for the low support of the hypothesis that Myzostomida belongs to Annelida in the results of phylogenomic studies. Future phylogenetic studies concerning Myzostomida should include all of the basal lineages of Bilateria to avoid directly neglecting the stand-alone basal position of Myzostomida as a potential hypothesis.     

The production of γ-linolenic acid by selected members of the Dikaryomycota grown on different carbon sources

In this study, seven fungal strains, representing different phylogenetic groups within the Dikaryomycota, were tested for the presence of -linolenic acid [18:3(6)], when grown in synthetic liquid media devoid of fatty acids, on a series of 40 different carbon sources. The fungal strains represented the species Dipodascopsis uninucleata, Eurotium rubrum, Galactomyces geotrichum, Neurospora crassa, Saccharomyces cerevisiae, Spongipellis unicolor and Talaromyces flavus. Cultures were periodically harvested during growth and the fatty acids in the total lipids analysed as methyl esters, using gas chromatography and mass spectrometry. It was found that 18:3(6) is present in E. rubrum CBS 350.65, S. unicolor CBS 117.16 and in T. flavus CBS 310.38NT, when these strains were grown on certain carbon sources. No correlation between the growth phase of the organism and the presence of 18:3(6) could be detected. In order to confirm the production of 18:3(6), the lipid metabolism of two unrelated dikaryomycotan fungi (S. unicolor CBS 117.16 and E. rubrum CBS 350.65) grown on two different carbon sources each, was examined. Cultures of E. rubrum CBS 350.65 were grown on glucose and sorbose and cultures of S. unicolor CBS 117.16 on glucose and sucrose in synthetic liquid media with a C:N ratio of 50:1 (w/w). The total lipids of these cultures were fractionated and the fatty acids in the fractions analysed as methyl esters, using gas chromatography and mass spectrometry. The lipid metabolism of both E. rubrum CBS 350.65 and S. unicolor CBS 117.16 differed on the two carbon sources used. The ab initio production of 18:3(6) by E. rubrum CBS 350.65 in synthetic liquid media was confirmed. In contrast, the ab initio production of 18:3(6) by S. unicolor CBS 117.16 in synthetic liquid media could not be confirmed.     

The Effects of Transmembrane Sequence and Dimerization on Cleavage of the p75 Neurotrophin Receptor by γ-Secretase

Cleavage of transmembrane receptors by γ-secretase is the final step in the process of regulated intramembrane proteolysis (RIP) and has a significant impact on receptor function. Although relatively little is known about the molecular mechanism of γ-secretase enzymatic activity, it is becoming clear that substrate dimerization and/or the α-helical structure of the substrate can regulate the site and rate of γ-secretase activity. Here we show that the transmembrane domain of the pan-neurotrophin receptor p75^NTR, best known for regulating neuronal death, is sufficient for its homodimerization. Although the p75^NTR ligands NGF and pro-NGF do not induce homerdimerization or RIP, homodimers of p75^NTR are γ-secretase substrates. However, dimerization is not a requirement for p75^NTR cleavage, suggesting that γ-secretase has the ability to recognize and cleave each receptor molecule independently. The transmembrane cysteine 257, which mediates covalent p75^NTR interactions, is not crucial for homodimerization, but this residue is required for normal rates of γ-secretase cleavage. Similarly, mutation of the residues alanine 262 and glycine 266 of an AXXXG dimerization motif flanking the γ-secretase cleavage site within the p75^NTR transmembrane domain alters the orientation of the domain and inhibits γ-secretase cleavage of p75^NTR. Nonetheless, heteromer interactions of p75^NTR with TrkA increase full-length p75^NTR homodimerization, which in turn potentiates the rate of γ-cleavage following TrkA activation independently of rates of α-cleavage. These results provide support for the idea that the helical structure of the p75^NTR transmembrane domain, which may be affected by co-receptor interactions, is a key element in γ-secretase-catalyzed cleavage.     

The Chromatin “Landscape” of a Murine Adult β-Globin Gene Is Unaffected by Deletion of Either the Gene Promoter or a Downstream Enhancer

In mammals, the complex tissue- and developmental-specific expression of genes within the β-globin cluster is known to be subject to control by the gene promoters, by a locus control region (LCR) located upstream of the cluster, and by sequence elements located across the intergenic regions. Despite extensive investigation, however, the complement of sequences that is required for normal regulation of chromatin structure and gene expression within the cluster is not fully defined. To further elucidate regulation of the adult β-globin genes, we investigate the effects of two deletions engineered within the endogenous murine β-globin locus. First, we find that deletion of the β2-globin gene promoter, while eliminating β2-globin gene expression, results in no additional effects on chromatin structure or gene expression within the cluster. Notably, our observations are not consistent with competition among the β-globin genes for LCR activity. Second, we characterize a novel enhancer located 3′ of the β2-globin gene, but find that deletion of this sequence has no effect whatsoever on gene expression or chromatin structure. This observation highlights the difficulty in assigning function to enhancer sequences identified by the chromatin “landscape” or even by functional assays.     

Phylogenetic Analysis of the Spider Mite Sub-Family Tetranychinae (Acari: Tetranychidae) Based on the Mitochondrial COI Gene and the 18S and the 5′ End of the 28S rRNA Genes Indicates That Several Genera Are Polyphyletic

The spider mite sub-family Tetranychinae includes many agricultural pests. The internal transcribed spacer (ITS) region of nuclear ribosomal RNA genes and the cytochrome c oxidase subunit I (COI) gene of mitochondrial DNA have been used for species identification and phylogenetic reconstruction within the sub-family Tetranychinae, although they have not always been successful. The 18S and 28S rRNA genes should be more suitable for resolving higher levels of phylogeny, such as tribes or genera of Tetranychinae because these genes evolve more slowly and are made up of conserved regions and divergent domains. Therefore, we used both the 18S (1,825–1,901 bp) and 28S (the 5′ end of 646–743 bp) rRNA genes to infer phylogenetic relationships within the sub-family Tetranychinae with a focus on the tribe Tetranychini. Then, we compared the phylogenetic tree of the 18S and 28S genes with that of the mitochondrial COI gene (618 bp). As observed in previous studies, our phylogeny based on the COI gene was not resolved because of the low bootstrap values for most nodes of the tree. On the other hand, our phylogenetic tree of the 18S and 28S genes revealed several well-supported clades within the sub-family Tetranychinae. The 18S and 28S phylogenetic trees suggest that the tribes Bryobiini, Petrobiini and Eurytetranychini are monophyletic and that the tribe Tetranychini is polyphyletic. At the genus level, six genera for which more than two species were sampled appear to be monophyletic, while four genera (Oligonychus, Tetranychus, Schizotetranychus and Eotetranychus) appear to be polyphyletic. The topology presented here does not fully agree with the current morphology-based taxonomy, so that the diagnostic morphological characters of Tetranychinae need to be reconsidered.     

Analysis of the Optimal Duration of Behavioral Observations Based on an Automated Continuous Monitoring System in Tree Swallows (Tachycineta bicolor): Is One Hour Good Enough?

Studies of animal behavior often rely on human observation, which introduces a number of limitations on sampling. Recent developments in automated logging of behaviors make it possible to circumvent some of these problems. Once verified for efficacy and accuracy, these automated systems can be used to determine optimal sampling regimes for behavioral studies. Here, we used a radio-frequency identification (RFID) system to quantify parental effort in a bi-parental songbird species: the tree swallow (Tachycineta bicolor). We found that the accuracy of the RFID monitoring system was similar to that of video-recorded behavioral observations for quantifying parental visits. Using RFID monitoring, we also quantified the optimum duration of sampling periods for male and female parental effort by looking at the relationship between nest visit rates estimated from sampling periods with different durations and the total visit numbers for the day. The optimum sampling duration (the shortest observation time that explained the most variation in total daily visits per unit time) was 1h for both sexes. These results show that RFID and other automated technologies can be used to quantify behavior when human observation is constrained, and the information from these monitoring technologies can be useful for evaluating the efficacy of human observation methods.     

The effect of zinc on the 5α-reduction of testosterone by the hyperplastic human prostate gland

The present studies were performed to evaluate the role of zinc in the regulation of testosterone 5α-reduction by the 800 g supematants prepared from human benign prostate hyperplasia specimens. The results show that when zinc is added at low concentrations the 5α-reduction of testosterone is increased but at higher cation concentrations the metabolism is significantly inhibited. This decrease was mediated by both a non-competitive inhibition of the binding of testosterone to the 5α-reductase enzyme and by a reduction in the formation of the NADPH cofactor. We have also demonstrated that the decreased synthesis of NADPH was produced by a competitive inhibition of both G6P and NADP binding to the G6PD enzyme. The data also suggests that the increase in testosterone metabolism observed at low zinc concentrations does not produce any changes in the binding of testosterone to the 5α-reductase enzyme. In spite of the above observations we were unable to establish any correlation between the endogenous zinc content of the tissue and the the in vitro capacity of the BPH samples to 5α-reduce testosterone. The present study suggests a possible physiological role for the regulation of testosterone metabolism by zinc in the human prostate gland.     

The formation of cholest-5-ene-3β,26-diol as an intermediate in the conversion of cholesterol into bile acids by liver mitochondria

1. When [(14)C]cholesterol was incubated with rat liver mitochondria, radioactive 26-hydroxycholesterol, 3beta-hydroxychol-5-enoic acid and other bile acids were isolated from the incubation mixture. 2. In the absence of added 26-hydroxycholesterol, the specific radioactivity of the 26-hydroxycholesterol formed from [(14)C]cholesterol during the incubation was higher than that of the 3beta-hydroxychol-5-enoic acid. Addition of increasing amounts of 26-hydroxycholesterol led to a progressive fall in the specific radioactivity, and to a progressive increase in the mass, of the 3beta-hydroxychol-5-enoic acid recovered at the end of the incubation. 3. It is concluded that 26-hydroxycholesterol is an intermediate in the formation of 3beta-hydroxychol-5-enoic acid from cholesterol. 4. Comparison of the specific radioactivity of the 26-hydroxycholesterol formed in the incubation mixture with that of the added [(14)C]cholesterol indicates that endogenous cholesterol in mitochondria is accessible to cholesterol 26-hydroxylase.     

What Is Required to End the AIDS Epidemic as a Public Health Threat by 2030? The Cost and Impact of the Fast-Track Approach

In 2011 a new Investment Framework was proposed that described how the scale-up of key HIV interventions could dramatically reduce new HIV infections and AIDS-related deaths in low and middle income countries by 2015. This framework included ambitious coverage goals for prevention and treatment services for 2015, resulting in a reduction of new HIV infections by more than half, in line with the goals of the declaration of the UN High Level Meeting in June 2011. However, the approach suggested a leveling in the number of new infections at about 1 million annually—far from the UNAIDS goal of ending AIDS by 2030. In response, UNAIDS has developed the Fast-Track approach that is intended to provide a roadmap to the actions required to achieve this goal. The Fast-Track approach is predicated on a rapid scale-up of focused, effective prevention and treatment services over the next 5 years and then maintaining a high level of programme implementation until 2030. Fast-Track aims to reduce new infections and AIDS-related deaths by 90% from 2010 to 2030 and proposes a set of biomedical, behavioral and enabling intervention targets for 2020 and 2030 to achieve that goal, including the rapid scale-up initiative for antiretroviral treatment known as 90-90-90. Compared to a counterfactual scenario of constant coverage for all services at early-2015 levels, the Fast-Track approach would avert 18 million HIV infections and 11 million deaths from 2016 to 2030 globally. This paper describes the analysis that produced these targets and the estimated resources needed to achieve them in low- and middle-income countries. It indicates that it is possible to achieve these goals with a significant push to achieve rapid scale-up of key interventions between now and 2020. The annual resources required from all sources would rise to US$7.4Bn in low-income countries, US$8.2Bn in lower middle-income countries and US$10.5Bn in upper-middle-income-countries by 2020 before declining approximately 9% by 2030.     

A Pine Is a Pine and a Spruce Is a Spruce – The Effect of Tree Species and Stand Age on Epiphytic Lichen Communities

With an increasing demand for forest-based products, there is a growing interest in introducing fast-growing non-native tree species in forest management. Such introductions often have unknown consequences for native forest biodiversity. In this study, we examine epiphytic lichen species richness and species composition on the trunks of non-native Pinus contorta and compare these to the native Pinus sylvestris and Picea abies in managed boreal forests in northern Sweden across a chronosequence of age classes. Overall, we recorded a total of 66,209 lichen occurrences belonging to 57 species in the 96 studied forest stands. We found no difference in species richness of lichens between stands of P. contorta and P. sylvestris, but stands of P. abies had higher total species richness. However, species richness of lichens in stands of P. abies decreased with increasing stand age, while no such age effect was detected for P. contorta and P. sylvestris. Lichen species composition progressively diverged with increasing stand age, and in 30-year-old stands all three tree species showed species-specific assemblages. Epiphytic lichen assemblages in stands of 30-year-old P. contorta were influenced by greater basal area, canopy closure, and average diameter at breast height, P. abies stands by higher branch density and canopy closure, and stands of P. sylvestris by greater bark crevice depth. Differences in lichen species richness and composition were mainly explained by canopy closure and habitat availability, and the greater canopy closure in mature P. abies stands promoted the colonization and growth of calicioid lichen species. Our results indicate that the non-native P. contorta have similar species richness as the native P. sylvestris. The main difference in lichen species richness and composition is between P. abies and Pinus spp. in managed forests of boreal Sweden.     

Is economy of competitive cyclists affected by the anterior–posterior foot position on the pedal?

The primary purpose of this investigation was to test the hypothesis that cycling economy, as measured by rate of oxygen consumption (VO(2)) in healthy, young, competitive cyclists pedaling at a constant workrate, increases (i.e. VO(2) decreases) when the attachment point of the foot to the pedal is moved posteriorly on the foot. The VO(2) of 11 competitive cyclists (age 26.8+/-8.9 years) was evaluated on three separate days with three anterior-posterior attachment points of the foot to the pedal (forward=traditional; rear=cleat halfway between the head of the first metatarsal and the posterior end of the calcaneous; and mid=halfway between the rear and forward positions) on each day. With a randomly selected foot position, VO(2) was measured as each cyclist pedaled at steady state with a cadence of 90 rpm and with a power output corresponding to approximately 90% of their ventilatory threshold (VT) (mean power output 203.3+/-20.8 W). After heart rate returned to baseline, VO(2) was measured again as the subject pedaled with a different anterior-posterior foot position, followed by another rest period and then VO(2) was measured at the final foot position. The key finding of this investigation was that VO(2) was not affected by the anterior-posterior foot position either for the group (p=0.311) or for any individual subject (p>or=0.156). The VO(2) for the group was 2705+/-324, 2696+/-337, and 2747+/-297 ml/min for the forward, mid, and rear foot positions, respectively. The practical implication of these findings is that adjusting the anterior-posterior foot position on the pedal does not affect cycling economy in competitive cyclists pedaling at a steady-state power output eliciting approximately 90% of VT.