Adenylyl-(5′, 2′)-adenosine 5′-Phosphate ((2′-5′) pA-A) in Crude Crystals of 5′-Adenylic Acid Isolated from Nuclease P1 (Penicillium Nuclease) Digest of Technical Grade Yeast RNA

Adenylyl (5′,2′)-adenosine 5′-phosphate ((2′-5′)pA-A) was detected in crude crystals of 5′-AMP prepared from Penicillium nuclease (nuclease P₁) digest of a technical grade yeast RNA. While (3′–5′)A-A was split by nuclease P₁, spleen phosphodiesterase, snake venom phosphodiesterase or alkali, (2′–5′)A-A was not split by a usual level of nuclease P₁ or spleen phosphodiesterase. Nuclease P₁ digests of 12 preparations of technical grade yeast RNA tested were confirmed to contain (2′–5′)pA-A. Its content was about 1 to 2% of the AMP component of each RNA preparation. As poly(A) was degraded completely by the Penicillium enzyme into 5′-AMP without formation of any appreciable amount of (2′–5′)pA-A, the technical grade RNA is supposed to contain 2–5′ phosphodiester linkages in addition to 3′–5′ major linkages.     

Synthesis of Oligodeoxynucleotides Containing 4′-C-Aminoalkyl-thymidines and Their Thermal Stability and Nuclease-Resistance Properties

Abstract

To find the nuclease-resistant oligodeoxynucleotides (ODNs) with natural phosphodiester linkages, we designed and synthesized ODNs containing 4′-C-aminoalkylthymidines (1–4). We found that the ODNs containing 1, 2, 3 or 4 were more resistant to nucleolytic hydrolysis by both snake venom phosphodiesterase (a 3′-exonuclease) and DNase I (an endonuclease) than unmodified ODNs.     

检测大肠杆菌内c-di-GMP水平的双荧光素报告质粒的构建及应用

细菌通过调控第二信使环二鸟苷酸(cyclic diguanylate, c-di-GMP)而促进其适应环境、存活及致病。【目的】本研究旨在建立有效的c-di-GMP水平检测方法,为大肠杆菌内c-di-GMP水平检测提供便利条件。【方法】根据c-di-GMP核糖开关受体的调控方式、荧光报告基因等设计引物,通过重叠聚合酶链反应(overlap polymerase chain reaction, overlap PCR)和同源重组酶构成基于核糖开关的双荧光素报告质粒pAmCherry-Vc2EGFP(pACVcE),然后构建c-di-GMP代谢基因过表达菌株和缺失菌株,利用pACVcE检测大肠杆菌内c-di-GMP水平。【结果】OverlapPCR扩增产物与目的靶序列一致,测序结果证明pACVcE序列正确。表达c-di-GMP合成酶DgcZ的大肠杆菌胞内c-di-GMP水平显著升高,而表达c-di-GMP降解酶PdeK的大肠杆菌胞内c-di-GMP水平显著降低。禽致病性大肠杆菌的胞内c-di-GMP水平检测发现c-di-GMP降解酶基因pdeK缺失后胞内的c-di-GMP水平显著升高。【结...     

SATE (Aryl) Phosphotriester Series. II. Stability Studies and Physicochemical Parameters

Abstract

The stability of phosphotriester derivatives of 3′-azido-2′,3′-dideoxythymidine (AZT) bearing a S-pivaloyl-2-thioethyl (tBuSATE) group and various aryl residues derived from L-tyrosine was evaluated in biological media. The results demonstrate that such compounds give rise to intracellular delivery of the parent mononucleotide through esterase and phosphodiesterase hydrolytic steps, successively.     

Characterization of orthophosphate release from dissolved organic phosphorus by gel filtration and several hydrolytic enzymes

The molecular weight distribution of dissolved organic phosphorus (DOP) and the possible mechanisms of orthophosphate (Pi) release were examined by gel filtration and incubation with some hydrolytic enzymes. Sixty five percent of the DOP appeared to have apparent molecular weights between 300 to 10000 daltons. Less than 10% of the DOP estimated higher molecules greater than 10000 daltons. Alkaline phosphatase released Pi more easily from low molecular weight (< 1500 daltons) DOP than from high molecular weight fractions. While, addition of nucleases or phosphodiesterase alone did not appear Pi release from high molecular weight DOP compounds. Pi release from those DOP compounds increased markedly (more than 30%) when alkaline phosphatase was incubated with nucleases or phosphodiesterase. However, 60% of DOP did not release Pi when alkaline phosphatase was incubated with either enzymes.     

Syntheses of Phosphonate Analogues of Dideoxyadenosine (DDA)-, Dideoxycytidine (DDC)-, Dideoxyinosine (DDI)-, and Deoxythymidine (DDT)-5′-Monophosphates

Abstract

Phosphonate derivatives of ddA, ddC, ddI and ddT (5f, 5e, 5c, and 5a) were prepared by condensing the 5′-aldehydes with diphenyl triphenylphosphoranylidenemethylphosphonate, reducing the resultant olefins and hydrolyzing the phosphonate phenyl esters, sequentially, with base and then C. atrox phosphodiesterase.     

Alteration of thiol-disulphide homeostasis in acute tonsillopharyngitis

Objective: Thiol-disulphide homeostasis (TDH) has a critical role in various clinical disorders. We aimed to assess the association of TDH with acute tonsillopharyngitis (AT) in children.

Methods: This study included 94 (73 viral and 21 bacterial) tonsillopharyngitis patients and 88 control children. Their native thiol, total thiol, and disulphide levels were measured.

Results: Viral and bacterial tonsillopharyngitis patients had lower native thiol levels compared with healthy children (P?P?=?0.008, respectively). Both groups had lower total thiol levels compared with control children (P?=?0.002 for viral, P?=?0.011 for bacterial). The disulphide levels were lower in bacterial than in viral tonsillopharyngitis patients (P?=?0.04), and there was a significant difference between viral tonsillopharyngitis patients and the control group (P?P?P?=?0.017 for bacterial). The disulphide/native thiol and disulphide/total thiol ratios were significantly higher in viral (P?P?=?0.017 for both) than in healthy children. In all patients, a correlation was found between the levels of C-reactive protein (CRP) and native thiol (r?=??0.211, P?=?0.04), CRP and total thiol (r?=??0.217, P?=?0.036), white blood cell (WBC) and native thiol (r?=??0.228, P?=?0.002), WBC and total thiol (r?=??0.191, P?=?0.01), and WBC and disulphide (r?=?0.160, P?=?0.03).

Discussion: TDH is altered in AT in children. The alteration is more prominent in viral than in bacterial tonsillopharyngitis.     

Relaxant effects of selected sildenafil analogues in the rat aorta

A new series of sulfonamide derivatives of pyrazolo[4,3-e][1,2,4]triazine with chiral amino group has been synthesized and characterized. The compounds were tested for their relaxant effects in the rat aorta. Evaluation of prepared derivatives demonstrated that compound (8a) is probably a non-selective phosphodiesterase (PDE) inhibitor, as it induced aortic relaxation through endothelium-independent mechanism.     

Six new species of the subgenera Alloparadisa and Ashima (Diptera: Drosophilidae: Phortica) from Yunnan,China, with DNA barcoding information

Six new species of the genus Phortica are described from Yunnan, Southwest China: P. (Alloparadisa) kaibangya n. sp., P. (Ashima) semiannulata n. sp., P. (Ashima) dianmianensis n. sp., P. (Ashima) idiasta n. sp., P. (Ashima) menglian n. sp. and P. (Ashima) zhangyuanae n. sp. The 22 new DNA sequences of the mitochondrial COI gene with BOLD Process ID and GenBank accession numbers are provided for the six new species and six related known species from southern China: P. (Ashima) glabra, Chen & Toda, 2005 P. (Ashima) nudiarista Cheng & Chen, 2008, P. (Ashima) saltiaristula Chen & Wen, 2005, P. (Ashima) spinosa, Chen & Toda, 2005 P. (Ashima) symmetria Chen & Toda, 2005 and P. (Ashima) yiqini Zhu & Chen, 2017. The pairwise interspecific K-2P COI distances among all Chinese species of the subgenera Alloparadisa and Ashima are summarized. An identification key to males of all Chinese species of the subgenera Alloparadisa and Ashima is provided.     

Synthesis,Bioactivation and Anti-HIV Activity of 4-Acyloxybenzyl bis(Nucleosid-5′-yl) Phosphates

Abstract

4-Acyloxybenzyl bis(nucleosid-5′-yl) phosphates 7a-c and 9a-c were prepared as potential prodrugs of the anti-HIV nucleosides 3′-azido-3′-deoxythymidine (AZT) and 2′,3′-dideoxyinosine (ddI) or their 5′-monophosphates.

The anti-HIV activities of these triesters were determined in two T-cell lines. In a C8166 cell line they displayed activities comparable to and in some cases superior to AZT, but they also exhibited an increase in cytotoxicity. In a thymidine kinase deficient JM T-cell line the activity was reduced but was still superior to AZT. In the presence of porcine liver carboxyesterase (PLCE), triester 7b biodegrades to the diester 10 which, with phosphodiesterase, gives initially AZT monophosphate 3 and AZT.     

New records of Polypedilum Kieffer (Diptera: Chironomidae) from India

Adult males of Polypedilum (Polypedilum) exterflexus n. sp., P. (Tripodura) rectangulum n. sp. and life stages of P. (Tripodura) pruina Freeman are described from India. In addition, one species, Polypedilum clavipennae n. sp. with all the life stages not assigned to any one of the existing subgenera is also described, and it may be justified to erect it as a new subgenus in future.     

Synthesis and Properties of the Oligonucleotide N3′ →P5′ Phosphoramidates

Abstract

Uniformly modified oligonucleotide N3′ → P5′ phosphoramidates were synthesized. The prepared N3′ → P5′ phosphoramidates form extremely stable duplexes and triplexes with complementary nucleic acids. Moreover, these compounds are highly resistant to enzymatic hydrolysis by snake venom phosphodiesterase and cellular nucleases and they show high antisense activity in vitro and in vivo.     

1-(<Emphasis Type="Italic">N</Emphasis>-Trifluoroacetylamino)alkylphosphonic acids: synthesis and properties

Summary. The 1-(N-trifluoroacetylamino)alkylphosphonic acids (TFA-AA^P) – sub-products in the synthesis of O,O-dialkyl 1-(N-trifluoroacetylamino)alkylphosphonates and O,O-diethyl 1-aminoalkylphosphonates, were synthesized in two-stage transformations of 1-aminoalkylphosphonic acids including: trifluoroacetylation of 1-aminoalkylphosphonic acids (AA^P) using a trifluoroacetic anhydride/trifluoroacetic acid reagent (AA^P + TFAA/TFA→2) and subsequent hydrolysis of the intermediary compounds 2 into desired TFA-AA^P (2→TFA-AA^P). These intermediates 2 presented mixtures of the type of mixed anhydrides of TFAA and 1-(N-trifluoroacetylamino)alkylphosphonic, pyrophosphonic and polyphosphonic acids, which underwent rapid and quantitative conversion to corresponding TFA-AA^P during treatment with an excess of water. The title acids were isolated by direct evaporation of the corresponding post-reaction mixtures, and their physicochemical proprieties, including deacylation abilities, were determined. TFA-AA^P compounds can be re-converted into the starting amino acids AA^P under respectively mild conditions (AA^P→TFA-AA^P→AA^P).     

Modeling Markovian biological systems via optimization operators

A general, computer-oriented method permitting to derive Markovian models with required (desired) properties is suggested and illustrated by examples. The method is based on the concept of a transition matrices generating (tmg) optimization operator, which is defined as a pair involving a (linear) transformation T and the associate optimization problem L _T . When the latter one is solved a set of transition matrices with required properties (ergodicity, regularity etc.) is get by starting from a sequence of probability vectors {P _k } which expresses the test data. Since the corresponding measurements are inevitably subjected to errors, it is not required that {P _k } be reached in the step-wise evolution of the process. Instead, it is required to minimize the so-called v-distance with respect to the probability vectors {P _k }. The optimization is performed by taking into account some constraints expressing the prior-known properties of the chain. This enables to solve the following problem: Given a sequence of (measured) probability vectors {P _k }, find a sequence of transition matrices {P _k } leading to the smallest v-distance with respect to {P _k } subject to given constraints. Some fundamental properties of the resulting Markov chains are emphasized, which are useful in modeling concrete biological systems. Thus, more realistic Markovian models are obtained starting from test data, as compared with the methods using conventional means.     

Exploring the nature of the H-bonds between the human class II MHC protein,HLA-DR1 (DRB*0101) and the influenza virus hemagglutinin peptide,HA306-318, using the quantum theory of atoms in molecules

The nature of the H-bonds between the human protein HLA-DR1 (DRB*0101) and the hemagglutinin peptide HA306-318 has been studied using the Quantum Theory of Atoms in Molecules for the first time. We have found four H-bond groups: one conventional CO··HN bond group and three nonconventional CO··HC, π··HC involving aromatic rings and HN··HC_aliphatic groups. The calculated electron density at the determined H-bond critical points suggests the follow protein pocket binding trend: P1 (2,311) >> P9 (1.109) > P4 (0.950) > P6 (0.553) > P7 (0.213) which agrees and reveal the nature of experimental findings, showing that P1 produces by a long way the strongest binding of the HLA-DR1 human protein molecule with the peptide backbone as consequence of the vast number of H-bonds in the P1 area and at the same time the largest specific binding of the peptide Tyr308 residue with aromatic residues located at the binding groove floor. The present results suggest the topological analysis of the electronic density as a valuable tool that allows a non-arbitrary partition of the pockets binding energy via the calculated electron density at the determined critical points.     

发酵饲料对生长育肥猪结肠微生物发酵及菌群组成的影响

【目的】研究复合菌发酵饲料对生长育肥猪结肠发酵、结肠黏膜与结肠内容物菌群组成的影响。【方法】采用气相色谱法检测育肥猪结肠内容物中挥发性脂肪酸浓度;采用MiSeq高通量测序方法检测育肥猪结肠黏膜与内容物中细菌菌群组成。【结果】饲喂发酵饲料对结肠黏膜及内容物中菌群多样性无显著影响(P0.05);显著提高了猪结肠黏膜中魏斯菌属和柔嫩梭菌属的相对丰度(P0.05),提高了结肠内容物中魏斯菌属、Subdoligranulum菌属相对丰度(P0.05);饲喂发酵饲料对结肠内容物中pH、乳酸、乙酸、丙酸、异丁酸、戊酸、异戊酸和总挥发性脂肪酸浓度无显著影响(P0.05),但显著提高了结肠内容物中的丁酸水平(P0.05)。【结论】饲喂复合菌发酵饲料可在一定程度上影响育肥猪结肠中细菌菌群的组成,促进丁酸生成,对肠道健康具有改善作用。     

利福平对红裸须摇蚊幼虫肠道微生物群落结构及功能的潜在影响北大核心

【目的】摇蚊是水生生态系统中重要的昆虫种类之一,其肠道微生物与个体生长发育、环境适应等过程密切相关,本研究旨在探究抗生素处理对摇蚊幼虫肠道微生物群落结构及功能的潜在影响。【方法】利用16S rRNA基因扩增子测序技术对利福平处理的红裸须摇蚊(Propsilocerus akamusi)幼虫肠道内容物中的菌群进行分析和比较,应用Tax4Fun法对其肠道菌群功能进行预测。【结果】利福平处理能够改变红裸须摇蚊幼虫肠道群落结构和多样性,宿主肠道菌群中拟杆菌门(Bacteroidota)(P<0.05)以及脱铁杆菌门(Deferribacterota)(P<0.001)的相对丰度显著上升,而变形菌门(Proteobacteria)与厚壁菌门(Firmicutes)相对丰度有所下降。在属水平上,利福平处理使耶尔森菌属(Yersinia)、假单胞菌属(Pseudomonas)、脱硫弧菌属(Desulfovibrio)的相对丰度有所降低,其中脱硫弧菌属(Desulfovibrio)显著降低。与此同时,共线性网络分析表明利福平处理后细菌群落稳定性大幅下降,菌种之间关联性显著减弱。通过京都基因与基因组百科全书(Kyoto encyclopedia of genes and genomes,KEGG)通路注释预测出红裸须摇蚊幼虫肠道菌群基因与基因信息处理、新陈代谢、人类疾病等功能相关,利福平处理可以使肠道菌群基因的抗药性功能显著上升,而内分泌和代谢疾病功能显著下降。【结论】研究结果揭示了抗生素利福平对红裸须摇蚊幼虫肠道细菌群落结构及功能的潜在影响,为进一步探索摇蚊肠道菌群发挥的必要作用奠定理论基础。     

Oxidative stress is associated with decreased heart rate variability in patients with chronic kidney disease

Objectives: Elevated oxidative stress and reduced heart rate variability (HRV) is prevalent in patients with chronic kidney disease (CKD) and is associated with increased morbidity and mortality. Previous studies have identified a positive association between elevated oxidative stress and autonomic dysfunction, however this relationship has not yet been investigated in the CKD population.

Methods: Plasma was collected from 78 patients with stage 3–4 CKD (estimated glomerular filtration rate 25–60?ml/min/1.73?m²) for the assessment of oxidative stress, including plasma total F2-isoprostanes, glutathione peroxidase activity and total antioxidant capacity. Time and frequency HRV parameters were measured from a three lead electrocardiogram.

Results: Participants with elevated F2-isoprostanes had reduced HRV compared to patients with normal levels of F2-isoprostanes. A number of HRV parameters were found to be inversely correlated with F2-isoprostanes in all CKD patients, including SDNN (r?=??0.337; P?r?=??0.281, P?=?0.01), LF (r?=??0.315, P?r?=??0.288, P?=?0.01). Multiple linear regression found F2-isoprostanes to be an independent predictor of SDNN (r²?=?0.287, β?=??0.272, P?=?0.01).

Discussion: Oxidative stress is significantly and independently associated with HRV in patients with CKD. Identifying oxidative stress in the pathogenesis of autonomic dysfunction may help target therapeutic strategies.     

One-Pot Synthesis of an AZT Boranophosphate Conjugated with Tyrosine: A Potential Prodrug Candidate

Abstract

A one-pot synthesis of P-tyrosinyl(P-O)-5′-P-AZT boranophosphate 7 via a phosphoramidite method is described. The P-boranophosphate diastereomers were separated by RP-HPLC, and their structures were confirmed by NMR and MS.     

The effect of tumor necrosis factor alpha (-308G/a) and interferon gamma (+874T/a) polymorphisms on susceptibility to coronary heart disease

Abstract

Background: Coronary heart disease (CHD) is a chronic inflammatory disease, which is still regarded as a major cause of morbidity and mortality worldwide. Several studies have suggested that polymorphisms in cytokine genes are associated with the pathogenesis of CHD. The genotype distribution of Tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) genes polymorphisms have been shown to be different in various ethnic populations. This study was aimed to investigate the association of TNF-α-308?G/A and IFN-γ?+?874T/A polymorphisms with risk of CHD in an Iranian population.

Methods: A total of 187 unrelated subjects comprised 96 CHD patients and 91 healthy controls were enrolled in this cross-sectional study. The TNF-α-308?G/A and IFN-γ?+?874T/A polymorphisms were genotyped using amplification refractory mutation system-PCR (ARMS-PCR). The chi-square and logistic regression tests were used to calculate the odds ratios (ORs) as a measure of differences in genotype frequencies.

Results: A significant differences in the allelic and genotypic distribution of TNF-α-308?G/A and IFN-γ?+?874T/A polymorphisms was found between CHD patients and healthy controls (P?=?0.017, P?=?0.011, P?=?0.006 and P?=?0.002, respectively). Logistic regression analyses were also revealed statistically significant risk for CHD with respect to TNF-α-308?A and IFN-γ?+?874?T carriers either in crude or after adjustment for potential confounders (P?=?0.003 and P?=?0.006, respectively).

Conclusion: This study provides strong evidence supporting the association of TNF-α-308G/A and IFN-γ?+?874T/A polymorphisms with the increased risk of CHD. Therefore, these two cytokine polymorphisms may play a role in predisposition to coronary heart disease.