The Synthesis of 2′-C-Functionalised Nucleosides for Incorporation into Catalytic RNA

Abstract

Five 2′-C-functionalized nucleosides (1–5) have been prepared and incorporated into dinucleoside monophosphates. The effect of the functionality on the stability of the adjacent phosphodiester bond toward hydrolysis by nuclease enzymes and extremes of pH has been assessed.     

Molecular Dynamics of Phenylalanine Transfer RNA

Abstract

The atomic motions of yeast phenylalanine transfer RNA have been simulated using the molecular dynamics algorithm. Two simulations were carried out for a period of 12 picoseconds, one with a normal Van der Waals potential and the other with a modified Van der Waals potential intended to mimic the effect of solvent. An analysis of large scale motions, surface exposure, root mean square displacements, helical oscillations and relaxation mechanisms reveals the maintenance of stability in the simulated structures and the general similarity of the various dynamic features of the two simulations. The regions of conformational flexibility and rigidity for tRNA^Phe have been shown in a quantitative measure through this approach.     

Dynamics of Ribosomal RNA Structure

Abstract

The structural dynamics of ribosomal 5S RNAs have been investigated by probing single strandedness through enzymatic cleavage and chemical modification. This comparative study includes 5S rRNAs from E. coli, B. stearothermophilus, T. thermophilics, H. cutirubrum, spinach chloroplast, spinach cytomplasm, and Artemia salina. The structural studies support a unique tertiary interaction in eubacterial 5S rRNAs, involving nucleotides around positions 43 and 75. In addition long range structural effects are demonstrated in E. coli 5S rRNA due to the conversion of C to U at position 92.     

Arenesulfonylethoxycarbonyl- a Set of Amino Protecting Groups for DNA and RNA Synthesis

Abstract

Phenyl-, 4-chlorophenyl- and 4-nitrophenylsufonylethoxycarbonyl groups have been reported for the first time as the exocyclic amino protecting groups in nucleoside chemistry. They are all stable under the standard conditions of manipulations in phosphotriester and phosphiteamidite chemistry, they are removable both under the alkaline hydrolytic conditions and also under the influence of non-nucleophilic tertiary bases. N³-Phenyl- and 4-toluenesulfonylethoxycarbonyl derivatives of uridine have been also prepared and characterized by ¹⁵N-NMR spectroscopy, their stabilities under different conditions have been tested.     

长链非编码RNA CTO-S对伪狂犬病毒复制的影响

[目的]研究伪狂犬病毒(pseudorabies virus,PRV)的长链非编码RNA(long noncoding RNA,lncRNA)CTO-S对于病毒复制的影响.[方法]利用3'RACE和5'RACE鉴定CTO-S的全长序列.验证CTO-S是否具有编码多肽的能力.Red重组方法构建CTO-S缺失株以及回复突变...     

F-RNA噬菌体YM1肠道宿主分析

【背景】F-RNA噬菌体近年来常被作为水环境中诺如病毒污染的指示物。本课题组前期以大肠杆菌ATCC700891^T为宿主,从人便样中筛选出一株F-RNA噬菌体YM1,其与大肠杆菌噬菌体MS2亲缘关系最近,MS2宿主通常为含有性菌毛的雄性大肠杆菌。【目的】探索F-RNA噬菌体与其肠道宿主及诺如病毒之间的互作关系,筛选YM1的肠道宿主。【方法】采用选择性培养基筛选YM1阳性便样中的大肠杆菌并进行YM1侵染验证,结合16S rRNA基因扩增子测序分析YM1接种前后便样中的差异性菌群种类,对YM1阳性便样中潜在的YM1肠道宿主进行分析。【结果】筛选到351个大肠杆菌菌株,YM1侵染结果表明这些大肠杆菌均不是YM1的宿主;16S rRNA基因扩增子测序分析差异性菌种显示,Enterobacter sp. (OTU144)和Enterobacter sp. (OTU11)这2株肠杆菌属细菌的相对丰度在YM1感染后发生显著性的降低,表明该2种细菌可能为YM1的潜在肠道宿主。【结论】YM1具有严格的宿主特异性,便样中大肠杆菌并非YM1的肠道宿主,同时发现了2种YM1的潜在宿主,为进一步筛选分离YM1的肠道宿主提供了方向和依据。     

Implications of childhood obesity for adult health: findings from thousand families cohort study

ObjectiveTo determine whether being overweight in childhood increases adult obesity and risk of disease.DesignProspective cohort study.SettingCity of Newcastle upon Tyne.Participants932 members of thousand families 1947 birth cohort, of whom 412 attended for clinical examination age 50.ResultsBody mass index at age 9 years was significantly correlated with body mass index age 50 (r=0.24, P<0.001) but not with percentage body fat age 50 (r=0.10, P=0.07). After adult body mass index had been adjusted for, body mass index at age 9 showed a significant inverse association with measures of lipid and glucose metabolism in both sexes and with blood pressure in women. However, after adjustment for adult percentage fat instead of body mass index, only the inverse associations with triglycerides (regression coefficient= −0.21, P<0.01) and total cholesterol (−0.17, P<0.05) in women remained significant.ConclusionsLittle tracking from childhood overweight to adulthood obesity was found when using a measure of fatness that was independent of build. Only children who were obese at 13 showed an increased risk of obesity as adults. No excess adult health risk from childhood or teenage overweight was found. Being thin in childhood offered no protection against adult fatness, and the thinnest children tended to have the highest adult risk at every level of adult obesity.

What is already known on this topic

Many studies have found that body mass index in childhood is significantly correlated with body mass index in adulthoodObese children have been found to have higher all cause mortality as adults

What this study adds

No excess health risk from childhood overweight was foundChildhood body mass index was linked to adulthood body mass index but not percentage body fatOnly children who were obese at 13 showed a significant increased risk of obesity as adultsPeople who were thinnest as children and fattest as adults tended to have the highest adult risk     

Synthetic Templates and the RNA Polymerase of Influenza a Virus

Abstract

Polyadenylic acid (poly A) and polyguanylic acid (poly G) have been modified to give polymers containing and Gpm5C termini. Polymers containing methylated (Gpmf C) termini are inactive as templates for the RNA-dependent RNA polymerase of Influenza A virus.     

Urinary Modified Nucleosides as Tumor Markers

Abstract

Extracts of urinary nucleosides have been sequentially purified and examined by mass spectrometric analysis. Seventeen modified nucleosides have been unequivocally identified and a further five provisionally identified. While several nucleosides were found only in a small number of extracts, the occurrence and levels of others were found to correlate with the tumour type and stage.     

Zn2+ Promoted Hydrolysis of RNA

Abstract

The Zn²⁺ promoted hydrolysis of phosphodiester bonds of RNA has been studied by using a series of model compounds from dinucleoside monophosphates to oligo- and polynucleotides. The results will be discussed with respect to complex formation between the metal ion catalysts and substrates.     

An FT-IR Study of DNA and RNA Conformational Transitions at Low Temperatures

Abstract

Fourier Transform Infrared (FT-IR) spectra of solid samples of DNA and RNA obtained from freeze-drying at solid CO₂ and liquid nitrogen temperatures, have been recorded and correlation between the conformational transitions and spectral changes is proposed. It is concluded that an equilibrium exists between A, B and Z conformations at low temperatures for the DNA molecule, which is temperature dependent, whereas the RNA molecule exhibits only the A conformation. The results have been compared with the metal-adducts of DNA and RNA, where one of the conformations is predominant.

Marker infrared bands for the B conformer have been found to be the strong band at 825 cm^?1 (sugar conformer mode) and a band with medium intensity at 690 cm^?1 (guanine breathing mode). The A conformation showed characteristic bands at 810 and 675 cm^?1. The B to Z conformational transition was characterized by the strong absorption bands near 820-810 cm^?1 and at 665-600 cm^?1.     

An efficient approach to probe the bioactive transdermal components of traditional Chinese herbal patches by UHPLC-MS: Gutong patch as a case

BackgroundTraditional Chinese herbal patches (TCHPs) characterized by good patient adherence and few side effects have been widely used in the clinic. However, their bioactive transdermal components, which are key to the quality and efficacy, have rarely been investigated.PurposeEstablishing an approach to probe the bioactive transdermal components of TCHPs, using Gutong patch (GTP) as a case study.Study Design and MethodsGTP constituents were identified using ultrahigh-pressure liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). The identified GTP constituents were transferred to an ultrahigh-pressure liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-QqQ-MS/MS) method in a dynamic multiple reaction monitoring (dMRM) mode for sensitively targeted analysis of transdermal components present at low concentrations. The ex vivo transdermal components were rapidly probed using a percutaneous permeation model and the release kinetics of marker components was assessed to evaluate the release behavior of GTP. The in vivo transdermal components were then studied in a rat model of arthritis and the changes in concentration of 15 representative bioactive transdermal components with time were well revealed.ResultsA total of 120 phytochemical constituents have been identified in GTP extracts and 61 ex vivo transdermal components were targetedly detected. The release kinetics of GTP were evaluated by eight marker components and fitted to a zero-order kinetic model. In vivo, 62 and 40 transdermal components were observed in the skin and subcutaneous tissues of arthritic rats, respectively. The concentration-time changes of 15 representative transdermal components with documented bioactivities have been successfully exhibited after GTP administration.ConclusionWe established a feasible approach to probe the bioactive transdermal components of TCHPs efficiently. The integration of mass spectrometry profiling and targeted detection in dMRM mode enabled a comprehensive investigation of phytochemical constituents and their transdermal delivery, thus addressing the challenge of direct probing of diverse transdermal components present at low concentrations. This approach could be used to rapidly probe the bioactive components and understand the mechanism of TCHPs.     

Gender Differences in Anthropometric Predictors of Physical Performance in Older Adults

BackgroundBoth high body fat and low muscle mass have been associated with physical disability in older adults. However, men and women differ markedly in body composition; men generally have more absolute and relative lean muscle mass and less fat mass than women. It is not known how these anthropometric differences differentially affect physical ability in men and women.ObjectivesThis study examines differences in anthropometric predictors of physical performance in older women and men.MethodsParticipants were 470 older women and men 72.9 (7.9) years of age. Body composition was measured using dual-energy x-ray absorptiometry. Maximum leg strength and power were measured using a leg press. Muscle quality (MQ) was calculated as relative strength (leg press strength per kilogram of leg muscle mass). Gait speed and chair rise were used to assess mobility performance and functional strength.ResultsBody mass index (BMI), age, and MQ emerged as predictors (P < 0.05) of functional strength and mobility in men and women somewhat differently. After accounting for age and sample, leg MQ was related to chair rise time and gait speed in men but not women. BMI was related to gait speed in both men and women, but BMI was related to chair rise time only in women.ConclusionResults implicate the prioritized importance of healthy weight and muscle maintenance in older women and men for maintained physical functioning with aging.     

Purification of human seminal acrosin inhibitor and its kinetics

A low molecular mass, naturally occurring acrosin inhibitor has been identified and purified (490-7-fold) from human semen, and kinetic studies have been performed on the association characteristics as well as for the determination of affinity constants (K _i values). The results show thatK _i value (3.34 × 10⁻²) of the inhibitor towards human acrosin is almost three times lower than that of pancreatic trypsin, indicating a much higher specificity and inhibitory property for acrosin. The purified human seminal acrosin inhibitor has a molecular mass of 5.5 kDa and shows a single band using 10–20% gradient SDS PAGE. The work is of great significance for the development of more specific, nontoxic and irreversible inhibitors for human acrosin.     

Synthesis and Antiviral (RNA) Evaluation of Nucleoside Analogs of Tiazofurin Modified at the Carboxamide Moiety

Abstract

The carboxamide functionality of tiazofurin 1a has been modified to produce the following analogs: carboximidates 5a,b, carboxamidines 6, 10, tetrahydropyrimidine 7, N-glycine 8 and N-glutamine 9. These structural modifications abolished the in vitro antiviral (RNA) activity exhibited by tiazofurin against the flaviviruses (yellow fever and Japanese encephalitis viruses), bunyavirus (Punta Toro virus) and togavirus (Venezuelan equine encephalomyelitis virus). Only carboximidates 5a,b retained marginal activity against bunyaviruses.     

Identification of the COMM-domain containing protein 1 as specific binding partner for the guanine-rich RNA sequence binding factor 1

BackgroundThe guanine-rich RNA sequence binding factor 1 (GRSF1) is an RNA-binding protein of the hnRNP H/F family, which has been implicated in erythropoiesis, regulation of the redox homeostasis, embryonic brain development, mitochondrial function and cellular senescence. The molecular basis for GRSF1-RNA interaction has extensively been studied in the past but for the time being GRSF1 binding proteins have not been identified.MethodsTo search for GRSF1 binding proteins we first employed the yeast two-hybrid system and screened a cDNA library of human fetal brain for potential GRSF1 binding proteins. Subsequently, we explored the protein-protein-interaction of the recombiant proteins, carried out immunoprecipitation experiments to confirm the interaction of the native proteins in living cells and performed truncation studies to identify the protein-binding motif of GRSF1.ResultsUsing the yeast two-hybrid system we identified the COMM-domain containing protein 1 (COMMD1) as specific GRSF1 binding protein and in vitro truncation studies suggested that COMMD1 interacts with the alanine-rich domain of GRSF1. Co-immunoprecipitation strategies indicated that COMMD1-GRSF1 interaction was RNA independent and also occurred in living cells expressing the two native proteins.ConclusionIn mammalian cells the COMM-domain containing protein 1 (COMMD1) specifically interacts with the Ala-rich domain of GRSF1 in an RNA-independent manner.General significanceThis is the first report describing a specific GRSF1 binding protein.     

Synthesis and Physical Characterization of Bis 3′→5′ Cyclic Dinucleotides (NpNp): RNA Polymerase Inhibitors

Abstract

A defined chemical synthesis of the cyclic dinucleotides, ApAp, ApUp, and UpUp has been devised, based on modern phosphotriester methods. These cyclic dinucleotides have been shown to inhibit RNA polymerase. The ¹H NMR spectra of the protected dimers show a preference for the ²E form, while the spectra of the unprotected dimers show the ³E form to be favored. The circular dichroism spectra show a negative long wavelength transition; however, ApUp does not show the short wavelength maximum present in the spectra of APAP and UpUp.