The photochemistry of 5-BrdCpdC, dCp5-BrdCpdA, and dCp5-BrdCdT in aqueous solution

We isolated an intrastrand crosslink product from the Pyrex-filtered UV light irradiation of 5-BrdCpdC in aqueous solution. ESI-MS, MS/MS, and 2-D nuclear Overhauser effect spectroscopy (NOESY) results showed that the C5 carbon atoms of the two cytosines are covalently bonded. The same cross-link product can also be induced from the similar UV irradiation of dCp5-BrdCpdA and dCp5-BrdCpdT.     

Isolation and Characterization of 5-Carbamoylmethyluridine and 5-Carbamoylmethyl-2-Thiouridine from Human Urine

Abstract

Two new modified uracil nucleosides, 5-carbamoylmethyuridine (ncm⁵U, I) and 5-carbamoylmethyl-2-thiouridine (ncm⁵s²U, II) were isolated from a 24 hr collection of a normal human urine. The structures were assigned on the basis of UV, NMR and mass spectral data and confirmed by comparison of the spectral data and HPLC mobilities with those of authentic samples. On the basis of experimental data it appears possible that 5-carbamoylmethyl-2-thio-uridine (ncm⁵s²U, II) may be a degradation product produced from a labile precursor by the chemical treatments during the isolation procedure. However, the other nucleoside (ncm⁵U, I) certainly appears to be of metabolic origin and was also found in the urines of one chronic myelogenous leukemia and one lung carcinoma patient.     

Inactivation of murine norovirus, feline calicivirus and echovirus 12 as surrogates for human norovirus (NoV) and coliphage (F+) MS2 by ultraviolet light (254 nm) and the effect of cell association on UV inactivation

Aims: To determine inactivation profiles of three human norovirus (NoV) surrogate viruses and coliphage MS2 by ultraviolet (UV) irradiation and the protective effect of cell association on UV inactivation. Methods and Results: The inactivation rate for cell‐free virus or intracellular echovirus 12 was determined by exposure to 254‐nm UV light at fluence up to 100 mJ cm^?2. The infectivity of murine norovirus (MNV), feline calicivirus (FCV) and echovirus 12 was determined by cell culture infectivity in susceptible host cell lines, and MS2 infectivity was plaque assayed on Escherichia coli host cells. The UV fluencies to achieve 4‐log₁₀ inactivation were 25, 29, 30 and 70 (mJ cm^?2) for cell‐free FCV, MNV, echovirus 12 and MS2, respectively. However, a UV fluence of 85 mJ cm^?2 was needed to inactivate intracellular echovirus 12 by 4 log₁₀. Conclusions: Murine norovirus and echoviruses 12 are more conservative surrogates than FCV to predict the UV inactivation response of human NoV. Intracellular echovirus 12 was 2·8‐fold more resistant to UV irradiation than cell‐free one. Significance and Impact of the Study: Variation in UV susceptibilities among NoV surrogate viruses and a likely protective effect of cell association on virus susceptibility to UV irradiation should be considered for effective control of human NoV in water.     

Implication of the Nature and Texturation of Silicone Surfaces on the Grafting of PolyNaSS,a Bioactive Polymer

ObjectiveThe publication aims to characterize the particularities of breast implant outer shells' structure and roughness. Then, it seeks to study the implication of the topography and the type of silicone on the grafting of the bioactive polymer under UV irradiations.Material & methodsPolyNaSS was grafted on silicone surfaces via a radical polymerization under 365 nm UV irradiation. Surface characterizations were accessed using scanning electron microscopy (topography), water contact angle measurements, infrared spectroscopy, and colorimetric assays (grafting density). A viability test was carried with L929 fibroblasts using MTT reagent.ResultsPolydiphenylsiloxane (PDPS) has improved the grafting protocol thanks to the reactivity of phenyl groups under UV irradiation compared to polydimethylsiloxane (PDMS) but exhibits low viability rates in contact with fibroblasts.ConclusionThe roughness of silicone surfaces or the nature of silicone influence the grafting quality. PDPS could not be considered as an alternative to PDMS from a biological point of view.     

紫外辐照恢复早期耐辐射奇球菌的转录组学分析（英文）

目的 耐辐射奇球菌是一种对紫外线、电离、干燥和化学试剂具有较强抗性的极端微生物。然而，该菌在紫外辐照后恢复早期的分子响应还不完全清楚。本文的目的是揭示耐辐射奇球菌在这一阶段的转录组响应。方法 本研究采用RNA-seq技术，测定了正常和紫外辐照培养条件下耐辐射奇球菌的转录组。为确定关键的差异表达基因及其调控关系，进行了功能富集分析。选取部分关键差异表达基因，进行实时定量PCR实验验证。利用以往研究中的转录组数据，寻找紫外辐照、电离辐射和干燥胁迫条件下公共的差异表达基因。构建了蛋白质-蛋白质相互作用网络；对蛋白质互作网络中的枢纽基因和主要模块进行了鉴定；对这些枢纽基因和模块进行了功能富集分析。结果 紫外辐照后的恢复早期，上调基因数量是下调基因数量的2倍以上，且多数与应激反应和DNA修复有关。恢复早期的修复途径主要有单链退火（SSA）途径（涉及基因：ddr A-D）、非同源端连接（NHEJ）途径（涉及基因：lig B、ppr A）和核苷酸切除修复（NER）途径（涉及基因：uvr A-C），前两种途径为同源重组（HR）做准备，而NER途径去除紫外线照射带来的嘧啶二聚体。通过比较紫外辐照、电离辐...     

Inducible reactivation of UV-irradiated cholera phage e5 in Vibrio cholerae MAK757

Summary The survival of UV-irradiated cholera phage e5 was found to increase when the host cells, Vibrio cholerae MAK757, were exposed to a low dose of UV irradiation before phage infection (Weigle reactivation), indicating the existence of a UV-inducible DNA repair pathway (SOS repair) in V. cholerae MAK757. The induction signal generated by UV irradiation was transient in nature and lasted about 20–30 min at 37°C. Maximal weigle reactivation of the phage was obtained when the host cells were irradiated with a UV dose of 16 J/m². V. cholerae MAK757 was also found to possess efficient photoreactivation and host cell reactivation of UV-damaged DNA in phage e5.     

Protoplast Mutation and Genome Shuffling Induce the Endophytic Fungus Tubercularia sp. TF5 to Produce New Compounds

Tubercularia sp. TF5 is an endophytic fungal strain isolated from the medicinal plant Taxus mairei. Previously, taxol has been detected in the fermentation products of this strain. However, it lost the capability of producing taxol after long-term laboratory culture. Herein, we tried to reactivate the production of taxol by protoplast mutations and genome shuffling. The protoplasts of Tub. sp. TF5 were prepared from its mycelia, and mutated by UV and NTG. The mutant strains regenerated from the mutated protoplasts were selected and classified into four groups on the basis of their phenotypes, the profile of their metabolites analyzed by TLC, MS, and bioassay data. Then, genome shuffling was subsequently carried out with eight mutant strains, with two representatives from each protoplast mutant group, and genome shuffling mutant strains were obtained and screened using the same screening procedure. Although taxol has not been detected in any mutant, two important mutants, M-741 and G-444 were selected for metabolites isolation and determination due to their phenotypes, and differences in TLC analysis result from TF5 and other mutants. Three new sesquiterpenoids, namely tuberculariols A–C (1–3), and a known dihydroisocoumarin (4) were obtained from M-741. Eighteen novel compounds were isolated from G-444, including five new sesquiterpenoids (5-9), two new dihydroisocoumarins (10, 11), one new tetralone (12), together with 10 known compounds (13–20, 1, and 2). The compounds isolated from the M-741 and G-444 were different in structure types and substitutions from those of TF5 (15, 21–29). The results showed, for the first time, that protoplast mutations and genome shuffling are efficient approaches to mining natural products from endophytic fungi. Understanding the mechanisms of unlocking the biosynthesis of new metabolites will facilitate the manipulation of the secondary metabolism in fungi.     

UV Light-Induced Crosslinking of the Strands of Poly(dA-dT) and Related Alternating Purine-Pyrimidine DNAs

Abstract

Alkaline agarose gel electrophoresis was used to detect UV-induced crosslinking of the strands of poly(dA-dT) and related alternating purine-pyrimidine DNAs in solutions stabilizing various polynucleotide conformations. Strands of the B-form and A-form of poly(dA-dT) were not crosslinked but a UV dose-dependent retarded species appeared in the denaturing gels in parallel with the polynucleotide isomerization into the unusual X-form. Most other polynucleotides adopting the X-form were crosslinked as well. The exceptions include the X-forms of poly(dA-butyl⁵dU) and poly(dA-pentyl⁵dU) whose strands do not crosslink because the long exocyclic substituents attached to uracil make the photodimerization impossible. Strands of poly (amino²dA-dT) and poly(dA, amino ²dA-dT), the latter polynucleotide containing roughly equal amounts of amino ²adenine and adenine, also do not crosslink upon UV irradiation because they isomerize into an A-like conformation which is different from the X- form of poly (dA-dT). In contrast, strands of the mixed copolymers of poly(dA, amino ²dA-dT) containing low amino ²adenine contents are crosslinked upon UV irradiation, in accordance with the observation that they isomerize into the X-form.     

A concise synthesis of peramine,a metabolite of endophytic fungi

ABSTRACT

The total synthesis of peramine, a natural product isolated from an endophytic fungi, has been achieved in four steps and 34% overall yield from known compounds. The key step was the one-pot construction of the pyrrolopyrazinone ring from pyrrole amide and propargyl bromide. The preparation of peramine-d₄ as an internal standard for quantitative analysis by MS is also described.     

内生链霉菌SAT1转录组分析和抑菌代谢产物的鉴定

【背景】植物内生链霉菌Streptomyces sp.SAT1分离自药用植物荠苨根部,对多种植物病原真菌和病原细菌具有强抑菌活性,在农林业生物防治领域应用潜力巨大。【目的】揭示该菌在不同培养基条件下的抑菌效果和抑制细菌的活性物质类型,为该菌生物防治应用提供理论基础和技术支撑。【方法】通过测定发酵液和菌体萃取物的抑菌活性,研究培养基成分对抑菌活性物质生物合成的影响;选择抑制细菌活性高和无抑菌活性的培养基进行发酵,通过转录组测序分析差异表达基因的功能,并利用紫外吸收光谱和UPLC-MS/MS鉴定活性物质的成分。【结果】所选用的7种链霉菌常用发酵培养基中,无论发酵液还是菌体萃取物,TSB、GS和R5培养基无抑制细菌活性;PDB、ISP2、MS和H有较强的抑菌活性。对PDB、ISP2和TSB发酵菌体进行转录组测序分析,共发现差异表达基因3 567个,KEGG富集分析发现差异基因多集中在global and overview maps、氨基酸代谢和碳水化合物代谢等通路上,而且与TSB比,PDB和ISP2分别有18个和5个上调基因定位于moenomycin类物质的生物合成基因簇上。以标准品为对照,...     

Photochemistry of the O-Nitrobenzyl Protecting Group in RNA Synthesis

Abstract

UV irradiation of 2′-O (o-nitrobenzyl)adenylyl(3′-5′)uridine in the presence of O₂ yields the corresponding nitrobenzoyl derivative in addition to the expected A-U. A mechanism proposed for this oxidation involves the successive removal of the two benzylic protons with a hydroperoxide as the intermediate between the two steps.     

Preparation of Oligonucleotides Containing 5-Bromouracil and 5-Methylcytidine.

Abstract

A previously described side reaction on 5-bromouracil during standard oligonucleotide deprotection conditions has been studied in detail. The side product, 5-amino-2′-deoxyuridine, is isolated and characterized. The use of several 5-methylcytidine protected derivatives for the preparation of oligonucleotides containing 5-bromouracil and 5-methylcytidine free of 5-amino-2′-deoxyuridine is discussed.     

Identification and Synthesis Of 5′-Deoxyxanthosine,a Novel Nucleoside in Normal Human Urine1

Abstract

Methods used in the identification and synthesis of 5′-deoxyxanthosine (5′-dX), a novel nucleoside found in normal human urine, are described. The urine sample was separated into nucleoside components by HPLC. Low and high resolution GC/MS techniques were then used to assign a tentative structure of the new nucleoside as 5′-dX. Finally, after biochemical synthesis, a comparison of the reference material with the urinary sample using mass spectrometry confirmed the structure as 5′-dX.     

Synthesis of (3E, 5Z)-3,5-Dodecadienylacetate,the Sex Pheromone of Phtheochroa cranaodes (Lepidoptera: Tortricidae)

(3E, 5Z)-3,5-Dodecadienyl acetate, the female sex pheromone of Phtheochroa cranaodes, was regio and stereo-selectively synthesized from 1-octyne and (E)-4-bromo-3-buten-1-ol by using Pd(PPh₃)₄, CuI and piperidine to afford the enyne (5). Further elaboration afforded the target pheromone. The synthetic pheromone was identified with the natural product by its MS and IR, data GLC retention time and biological activity.     

Rapid,Stepwise Substitution of Fluorines In 5-Trifluoromethyl-2′-Deoxyuridine by Bisulfite

Abstract

On treatment with bisulfite at neutral pH, 5-trifluoromethyl-2′-deoxyuridine (CF3dUR) underwent rapid substitution of the fluorine atoms by bisulfite to give first the monosulfonate and then the disulfonate derivatives. It was shown that the monosulfonate product has reactivity to bisulfite with a potency half that of CF3dUR. These findings demonstrate the stepwise nature of the fluorine release from CF3dUR and constitute evidence that 5-exo-methylene type intermediates are involved in the nucleophile-mediated release of the fluorine from CF3dUR.     

Dihydrofuro [2,3-b] quinolinium alkaloids in cultured cells of Ptelea trifoliata L.

Two dihydrofuroquinoline alkaloids, ptelefolonium and another new alkaloid, ptelecultinium, have been isolated from callus strains of Ptelea trifoliata L.. Ptelecultinium was not known to occur in the mature plants. The structure of these two alkaloids were established by UV, MS and ¹H-NMR spectra.     

Aromatic Photosubstitution Reactions for the Synthesis of 5-Aryl-2′-Deoxyuridines

Abstract

The title compounds can be prepared by ultraviolet irradiation of solutions of 5-iodo-2′-deoxyuridine and aromatic compounds or 2′-deoxyuridine and haloaromatic derivatives.     

Proteomics analysis of UV‐irradiated Lonicera japonica Thunb. with bioactive metabolites enhancement

A previous study showed that the contents of caffeoylquinic acids and iridoids, the major bioactive components in the postharvest Lonicera japonica Thunb., were induced by enhanced ultraviolet (UV)‐A or UV‐B irradiation. To clarify the UV‐responsive key enzymes in the bioactive metabolites biosynthetic pathway and the related plant defense mechanism in L. japonica, 2DE in combination with MALDI‐TOF/TOF MS was employed. Seventy‐five out of 196 differential proteins were positively identified. Based on the functions, these proteins were grouped into nine categories, covering a wide range of molecular processes including the secondary metabolites (caffeoylquinic acids and iridoids) biosynthetic‐related proteins, photosynthesis, carbohydrate and energy metabolism, stress, DNA, transport‐related proteins, lipid metabolism, amino acid metabolism, cell wall. Of note is the increasing expression of 1‐deoxy‐d ‐xylulose 5‐phosphate reductoisomerase and 5‐enol‐pyruvylshikimate‐phosphate synthase, which was crucial to supply more precursor for the secondary metabolites including caffeoylquinic acids and iridoids. Thus, this study provides both the clues at the protein level for the increase of the two bioactive components upon UV irradiation and the profile of UV‐responsive proteins in L. japonica.     

Synthesis and bioactivity of 5-(1-aryl-1H-tetrazol-5-ylsulfanylmethyl)-N-xylopyranosyl-1,3,4-oxa(thia)diazol-2-amines

A series of new N′-[N-(2,3,4-tri-O-acetyl-β-d-xylopyranosyl)thiocarbamoyl]-2-[(1-aryl-1H-tetrazol-5-yl)sulfanyl]acetohydrazides 5a–5e were synthesized rapidly in high yields from 2-(1-aryl-1H-tetrazol-5-ylsulfanyl)acetohydrazides 3a–3e and 2,3,4-tri-O-acetyl-β-d-xylopyranosyl isothiocyanate 4, then 5a–5e were converted to a series of new 5-(1-aryl-1H-tetrazol-5-ylsulfanylmethyl)-N-(2,3,4-tri-O-acetyl-β-d-xylopyranosyl)-1,3,4-oxadiazole-2-amines 6a–6e and 5-(1-aryl-1H-tetrazol-5-ylsulfanylmethyl)-N-(2,3,4-tri-O-acetyl-β-d-xylopyranosyl)-1,3,4-thiadiazole-2-amines 7a–7e, respectively under mercuric acetate/alcohol system or acetic anhydride/phosphoric acid system, then deacetylated in the solution of CH₃ONa/CH₃OH. All of the novel compounds were characterized by IR, ¹H NMR, ¹³C NMR, MS and elemental analysis. The structures of compounds 2e, 3e, 5a and 5c have been determined by X-ray diffraction analysis. Some of the synthesized compounds displayed PTP1B inhibition and microorganism inhibition.