吲哚/吲唑酰胺类合成大麻素检验方法研究进展

合成大麻素作为滥用最广泛、种类最多的新精神活性物质之一,严重影响人类身心健康和社会稳定,当前滥用较严重,常出现在国内外各类案件的侦办中,是世界范围内关于新精神活性物质案件的一个研究焦点,建立合成大麻素的检验方法对侦破相关案件具有重要意义.近几年出现的吲哚/吲唑酰胺类合成大麻素被称为第八代合成大麻素,其涉案频繁但研究相对...     

一株红球菌脱硫菌株脱硫特性的研究

从炼油厂污水排放口取得的土样中筛选到一株能降解二苯并噻吩 (DBT)的菌株 ,用GC/MS方法 ,证明其降解DBT走硫专一脱除途径 ,即“4S途径” .该菌株被命名为SDUZAWQ ,用微生物生理生化实验及 16SrDNA序列分析初步鉴定为红球菌属 (Rhodococcussp .) .实验结果表明 ,红球菌SDUZAWQ可有效降解苯并噻吩 (BT)和DBT及其甲基衍生物 .在 2d内 ,BT与DBT可同时完全降解 ,0 .5mmol·L-1的BT在 1d内可降解掉 86% ,降解速度高于DBT的降解 .5 MBT的降解率也高于 4,6 DMDBT和 4 MDBT .4 MDBT较 4,6 DMDBT更难降解 ,在 2d内 ,红球菌SDUZAWQ可降解 62 %的 4,6 DMDBT ,而相同条件下 ,4 MDBT仅能被降解 3 6% .     

A molecular docking model of SARS-CoV S1 protein in complex with its receptor, human ACE2

The exact residues within severe acute respiratory syndrome coronavirus (SARS-CoV) S1 protein and its receptor, human ACE2, involved in their interaction still remain largely undetermined. Identification of exact amino acid residues that are crucial for the interaction of S1 with ACE2 could provide working hypotheses for experimental studies and might be helpful for the development of antiviral inhibitor. In this paper, a molecular docking model of SARS-CoV S1 protein in complex with human ACE2 was constructed. The interacting residue pairs within this complex model and their contact types were also identified. Our model, supported by significant biochemical evidence, suggested receptor-binding residues were concentrated in two segments of S1 protein. In contrast, the interfacial residues in ACE2, though close to each other in tertiary structure, were found to be widely scattered in the primary sequence. In particular, the S1 residue ARG453 and ACE2 residue LYS341 might be the key residues in the complex formation.     

Allometric scaling laws of metabolism

One of the most pervasive laws in biology is the allometric scaling, whereby a biological variable Y is related to the mass M of the organism by a power law, Y=Y₀M^b, where b is the so-called allometric exponent. The origin of these power laws is still a matter of dispute mainly because biological laws, in general, do not follow from physical ones in a simple manner. In this work, we review the interspecific allometry of metabolic rates, where recent progress in the understanding of the interplay between geometrical, physical and biological constraints has been achieved.

For many years, it was a universal belief that the basal metabolic rate (BMR) of all organisms is described by Kleiber's law (allometric exponent b=3/4). A few years ago, a theoretical basis for this law was proposed, based on a resource distribution network common to all organisms. Nevertheless, the 3/4-law has been questioned recently. First, there is an ongoing debate as to whether the empirical value of b is 3/4 or 2/3, or even nonuniversal. Second, some mathematical and conceptual errors were found these network models, weakening the proposed theoretical arguments. Another pertinent observation is that the maximal aerobically sustained metabolic rate of endotherms scales with an exponent larger than that of BMR. Here we present a critical discussion of the theoretical models proposed to explain the scaling of metabolic rates, and compare the predicted exponents with a review of the experimental literature. Our main conclusion is that although there is not a universal exponent, it should be possible to develop a unified theory for the common origin of the allometric scaling laws of metabolism.     

An efficient method for recovery of target ssDNA based on amino-modified silica-coated magnetic nanoparticles

In this paper, an improved recovery method for target ssDNA using amino-modified silica-coated magnetic nanoparticles (ASMNPs) is reported. This method takes advantages of the amino-modified silica-coated magnetic nanoparticles prepared using water-in-oil microemulsion technique, which employs amino-modified silica as the shell and iron oxide as the core of the magnetic nanoparticles. The nanoparticles have a silica surface with amino groups and can be conjugated with any desired bio-molecules through many existing amino group chemistry. In this research, a linear DNA probe was immobilized onto nanoparticles through streptavidin conjugation using covalent bonds. A target ssDNA(I) (5′-TMR-CGCATAGGGCCTCGTGATAC-3′) has been successfully recovered from a crude sample under a magnet field through their special recognition and hybridization. A designed ssDNA fragment of severe acute respiratory syndrome (SARS) virus at a much lower concentration than the target ssDNA(I) was also recovered with high efficiency and good selectivity.     

Recognition and elimination of diversified pathogens in insect defense systems

Summary The elimination of infectious non-self by the host defense systems of multicellular organisms requires a variety of recognition and effector molecules. The diversity is generated in somatic cells or encoded in the germ-line. In adaptive immunity in jawed vertebrates, the diversity of immunoglobulins and antigen receptors is generated by gene rearrangements in somatic cells. In innate immunity, various effector molecules and pattern recognition receptors, such as antimicrobial peptides and peptidoglycan recognition proteins, are encoded in the germ-line of multicellular organisms, including insects and jawed vertebrates. In the present review, we discuss how insect host defense systems recognize and eliminate a multitude of microbes via germ-line-encoded molecules, including recent findings that a Drosophila member of the immunoglobulin superfamily is extensively diversified by alternative splicing in somatic immune cells and participates in the elimination of bacteria.     

Applications of Infrared Spectroscopy to Biochemical,Food, and Agricultural Processes

Abstract

Integrated investigations on infrared spectroscopic characteristics of metabolites and on applications of infrared spectroscopy to foodstuff production, food processing, and tasting are described. As the important metabolites, saccharides, which play very important roles in various functions, located in the central position of the metabolic pathways, were selected, and the spectral features of the saccharides and related materials are discussed. Additionally, the applications of spectral analysis to the monitoring of the enzyme reaction and the sugar metabolic processes, which are the main materials in food processing, are described. Furthermore, the studies on the spectroscopic measurements during the cultivation of agricultural products as foodstuffs and in the tasting as the final quality evaluation of foods are represented. These results suggest that infrared spectroscopy could be very effective for evaluating foodstuff production and the tasting of the processed foods and that the applied topics should provide fundamental information about the spectral behavior of the metabolites and bioproducts.     

Personalized Metabolic Profile by Synergic Use of NMR and HRMS

A new strategy that takes advantage of the synergism between NMR and UHPLC–HRMS yields accurate concentrations of a high number of compounds in biofluids to delineate a personalized metabolic profile (SYNHMET). Metabolite identification and quantification by this method result in a higher accuracy compared to the use of the two techniques separately, even in urine, one of the most challenging biofluids to characterize due to its complexity and variability. We quantified a total of 165 metabolites in the urine of healthy subjects, patients with chronic cystitis, and patients with bladder cancer, with a minimum number of missing values. This result was achieved without the use of analytical standards and calibration curves. A patient’s personalized profile can be mapped out from the final dataset’s concentrations by comparing them with known normal ranges. This detailed picture has potential applications in clinical practice to monitor a patient’s health status and disease progression.     

Photoacoustic microscopy

Photoacoustic microscopy (PAM) is a hybrid in vivo imaging technique that acoustically detects optical contrast via the photoacoustic effect. Unlike pure optical microscopic techniques, PAM takes advantage of the weak acoustic scattering in tissue and thus breaks through the optical diffusion limit (∼1 mm in soft tissue). With its excellent scalability, PAM can provide high‐resolution images at desired maximum imaging depths up to a few millimeters. Compared with backscattering‐based confocal microscopy and optical coherence tomography, PAM provides absorption contrast instead of scattering contrast. Furthermore, PAM can image more molecules, endogenous or exogenous, at their absorbing wavelengths than fluorescence‐based methods, such as wide‐field, confocal, and multi‐photon microscopy. Most importantly, PAM can simultaneously image anatomical, functional, molecular, flow dynamic and metabolic contrasts in vivo. Focusing on state‐of‐the‐art developments in PAM, this Review discusses the key features of PAM implementations and their applications in biomedical studies.     

Metabolic profiles of ribociclib in rat and human liver microsomes using liquid chromatography combined with electrospray ionization high-resolution mass spectrometry

Ribociclib is a highly specific CDK4/6 inhibitor. Determination of the metabolism of ribociclib is required during the drug development stage. In this study, metabolic profiles of ribociclib were investigated using rat and human liver microsomes. Metabolites were structurally identified by liquid chromatography electrospray ionization high-resolution mass spectrometry operated in positive-ion mode. The metabolites were characterized by accurate masses, MS² spectra and retention times. With rat and human liver microsomes, a total of 10 metabolites were detected and further identified. No human-specific metabolites were detected. The metabolic pathways of ribociclib were oxygenation, demethylation and dealkylation. Most importantly, two glutathione (GSH) adducts were identified in human liver microsomes fortified with GSH. The formation of the GSH adducts was hypothesized to be through the oxidation of electron-rich 1,4-benzenediamine to a 1,4-diiminoquinone intermediate, which is highly reactive and can be trapped by GSH to form stable metabolites. The current study provides an overview of the metabolic profiles of ribociclib in vitro, which will be of great help in understanding the efficacy and toxicity of this drug.