Detection of human serum albumin using a rare-earth nanosheet fluorescent probe based on intensity and lifetime signals.

Human serum albumin (HSA) is an important biomarker for early disease diagnosis. Therefore, the detection of HSA in biological samples is important. In this study, for the sensitive detection of HSA, a fluorescent probe based on Eu(III)-doped yttrium hydroxide nanosheets was designed and sensitized by α-thiophenformyl acetone trifluoride as an antenna. The morphology and structure of the as-prepared nanosheet fluorescent probe were studied by transmission electron microscopy and atomic force microscopy. A detailed investigation of the fluorescence properties of the as-obtained nanosheet probe revealed that the Eu(III) emission intensity was linearly and selectively enhanced by the consecutive addition of HSA. Furthermore, the lifetime signal of this probe was enhanced with increasing concentration. The sensitivity of the nanosheet probe to HSA is discussed based on the results of ultraviolet-visible, fluorescence, and infrared spectral analyses, the findings demonstrate that the nanosheet fluorescent probe we prepared is a highly sensitive and selective tool for detecting HSA concentration with a high intensity and a large lifetime change.

Evolution and structural variations in chloroplast tRNAs in gymnosperms.

BACKGROUND: Chloroplast transfer RNAs (tRNAs) can participate in various vital processes. Gymnosperms have important ecological and economic value, and they are the dominant species in forest ecosystems in the Northern Hemisphere. However, the evolution and structural changes in chloroplast tRNAs in gymnosperms remain largely unclear. RESULTS: In this study, we determined the nucleotide evolution, phylogenetic relationships, and structural variations in 1779 chloroplast tRNAs in gymnosperms. The numbers and types of tRNA genes present in the chloroplast genomes of different gymnosperms did not differ greatly, where the average number of tRNAs was 33 and the frequencies of occurrence for various types of tRNAs were generally consistent. Nearly half of the anticodons were absent. Molecular sequence variation analysis identified the conserved secondary structures of tRNAs. About a quarter of the tRNA genes were found to contain precoded 3' CCA tails. A few tRNAs have undergone novel structural changes that are closely related to their minimum free energy, and these structural changes affect the stability of the tRNAs. Phylogenetic analysis showed that tRNAs have evolved from multiple common ancestors. The transition rate was higher than the transversion rate in gymnosperm chloroplast tRNAs. More loss events than duplication events have occurred in gymnosperm chloroplast tRNAs during their evolutionary process. CONCLUSIONS: These findings provide novel insights into the molecular evolution and biological characteristics of chloroplast tRNAs in gymnosperms.

Characterization of the DNA molecular sequence of complete plastid genome of Paeonia rockii subsp. taibaishanica, an endemic species in China.

Paeonia rockii subsp. taibaishanica (Paeoniaceae), one of the tree peony species, is endemic to the Qinling Mountains in central China. In this study, we characterized its whole plastid genome sequence using the Illumina sequencing platform. The complete plastid genome size of P. rockii subsp. taibaishanica is 153,368 bp in length, including a large single copy (LSC) region of 85,030 bp, a small single copy (SSC) region of 17,042 bp, and a pair of inverted repeats (IRs) of 25,648 bp. The genome contains 131 genes, including 83 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The GC contents in chloroplast genome, LSC region, SSC region, and IR region were 38.3%, 36.6%, 32.6%, and 43.1%, respectively. A total of 16 species are used to construct the phylogenetic tree of Paeoniaceae, the results showed that P. rockii subsp. taibaishanica is more closely related with congeneric Paeonia suffruticosa and Paeonia ostii, these species were clustered into a clade with high bootstrap support.

Controllable enzymatic superactivity of α-chymotrypsin activated by the electrostatic interaction with cationic gemini surfactants.

Surfactant plays a critical role in enzymatic multi-functionalization processes. However, a deep understanding of surfactant-enzyme interactions has been lacking up until now due to the extreme complexity of the mixed system. This work reported the effect of cationic gemini surfactants, alkanediyl-α,ω-bis(dimethyldodecylammonium bromide) (C12C S C12Br2, S = 2, 6, and 10) on the enzymatic activity and conformation of α-chymotrypsin (α-CT) in phosphate buffer solution (PBS, pH 7.3). The enzymatic activity was assessed by the rate of 2-naphthyl acetate (2-NA) hydrolysis measured by UV-vis absorption. The superactivity of α-CT in the presence of C12C S C12Br2 appears in the concentration region below the critical micelle concentration (cmc) of the surfactant, and its maximum superactivity is correlated to the spacer length of C12C S C12Br2. Subtle regulation of the charge density of headgroups of the cationic surfactant can be achieved through partial charge neutralization of cationic headgroups by introducing inorganic counterions or oppositely charged surfactant, demonstrating that the electrostatic interaction plays the crucial role for emergence of the superactivity. The interaction between C12C S C12Br2 (S = 2,6, and 10) and α-CT was characterized by isothermal titration calorimetry (ITC), and the obtained endothermic enthalpy change indicates that the interaction induces the change in conformation and enzymatic superactivity. The methodologies of fluorescence spectroscopy, circular dichroism (CD), and differential scanning calorimetry (DSC) show that the gemini surfactants with different spacer lengths induct and regulate the secondary, tertiary and even fourth structures of the protein. The present work is significant to get deeper insight into the mechanism of the activation and denaturation of enzymes.

miR­760 regulates skeletal muscle proliferation in rheumatoid arthritis by targeting Myo18b.

MicroRNAs serve an important role in the development of several diseases. Numerous genes regulate the skeletal muscle differentiation of C2C12 myoblasts. The role of miR­760 in rheumatoid arthritis (RA) has not been reported, to the best of our knowledge. Therefore, the aim of the present study was to examine the role of miR­760 in regulating skeletal muscle proliferation in RA. Potential genes functionally involved in the tarsal joint of a collagen­induced RA model were identified using Gene Expression Omnibus. Reverse transcription­quantitative PCR and western blot analyses were performed to determine the mRNA and protein expression levels. The proliferation, cell cycle progression and migration of C2C12 myoblasts were detected using Cell Counting Kit­8, flow cytometry and wound­healing assays, respectively. TargetScan was used to predict the potential target genes of miR­760, and this was verified using a dual­luciferase reporter assay. In the present study, myosin­18b (Myo18b) expression was determined to be downregulated in the RA model. Silencing Myo18b decreased the proliferation, abrogated the cell cycle progression, and reduced the migration and differentiation of C2C12 myoblasts. Expression levels of cyclin­dependent kinase 2, cyclin D1, matrix metalloproteinase (MMP)­2, MMP­9, myogenin and myosin heavy chain 6 were all decreased when Myo18b was silenced. Furthermore, overexpression of Myo18b induced opposing effects on C2C12 myoblasts. It was shown that Myo18b was a target gene of miRNA­760. Overexpression of miR­760 decreased proliferation, cell cycle progression, migration and differentiation in C2C12 myoblasts, and decreased the expression of Myo18b. The opposite results were observed when miR­760 was downregulated. In conclusion, miR­760 inhibited proliferation and differentiation by targeting Myo18b in C2C12 myoblasts. The results of the present study may contribute to understanding the mechanisms underlying RA skeletal muscle proliferation, and miR­760/Myo18b may serve as potential targets for treating patients with RA.

[Immunologic theory investigation and discussion of pain caused by lumbar intervertebral disc herniation (LDH)].

To explore the main clinical manifestation (lower back pain and ischialgia) of LDH with immunologic method and study the relationship and clinical significance of the cardinal symptom (pain) and immune comple (IC), macrophage (MP),interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor (TNF), prostaglandin E2 (PGE2), phosphatidase A2 (PLA2), nitrogen monoxidum (NO) expressing, finding a new way in order to prevention and cure of LDH. We will review immunologic theory of LDH pain.

[Investigations and analysis of traumatic condition of Longnan area in Wenchuan earthquake].

OBJECTIVE: To investigate and analyze the traumatic conditions of Longnan area of Gansu in Wenchuan earthquake, and to explore the measures coping with unexpected disasters. METHODS: A sample survey including questionnaire survey, interviews and other methods was adopted to investigate the conditions of affected population of Longnan area in earthquake, especially on the traumatic conditions, the injured causes, treatment methods. RESULTS: In the sample survey of a total of 1652 earthquake casualties, the dead were 16 and the patients with extremities fractures were 750 (45.4%). Organized and timely rescue of the wounded could reduce the complications and the mortality . CONCLUSION: Strengthening the prevention and treatment of earthquake trauma can effectively decrease the death rate and disabled rate.