Regulatory effects of lncRNA ATB targeting miR-200c on proliferation and apoptosis of colorectal cancer cells

This investigation was intended to elucidate whether long noncoding RNA (lncRNA)-activated by transforming growth factor-β (ATB) interacting with miR-200c could mediate colorectal cancer (CRC) progression, offering potential strategies for diagnosing and treating CRC. Here totally 315 patients with CRC were recruited, and their CRC tissues and adjacent normal tissues were gathered. Concurrently, four colon cancer cell lines (ie, SW620, Lovo, HCT116, and SW480) and the human colon mucosal epithelial cell line (NCM460) were also purchased. Moreover, si-ATB, si-NC, miR-200c mimic, miR-200c inhibitor, and miR-NC were prepared for transfection into the CRC cells, and their effects on CRC cell lines were evaluated based on the conduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, colony formation assay, and flow cytometry assay. Eventually, the Luciferase reporter gene assay was carried out to judge if there existed a targeted relationship between ATB and miR-200c. The results of Cox regression analyses suggested that overexpressed lncRNA ATB, underexpressed miR-200c, poor tumor differentiation, lymph-vascular invasion, and perineural invasion were symbolic of shortened survival of the patients with CRC (all P < .05). Besides, transfection of pcDNA3.1-ATB and miR-200c inhibitor could boost the viability and proliferation of Lovo and SW620 cell lines (all P < .05). Meanwhile, the expressions of p53 and p21 were also reduced under treatments of pcDNA3.1-ATB and miR-200c inhibitor (P < .05). In addition, CDK2 seemed to reverse the contribution of miR-200c to intensifying viability and proliferation of Lovo and SW420 cell lines (P < .05). Furthermore, ATB might downregulate miR-200c expression by targeting it (P < .05), and CDK2 was subjected to dual regulation of both ATB and miR-200c (P < .05). In conclusion, the lncRNA ATB/miR-200c/CDK2 signaling was responsible for intensified proliferation and prohibited apoptosis of CRC cells, which might provide effective approaches for diagnosing and treating CRC.     

Protein‐spanning water networks and implications for prediction of protein–protein interactions mediated through hydrophobic effects

Hydrophobic effects, often conflated with hydrophobic forces, are implicated as major determinants in biological association and self‐assembly processes. Protein–protein interactions involved in signaling pathways in living systems are a prime example where hydrophobic effects have profound implications. In the context of protein–protein interactions, a priori knowledge of relevant binding interfaces (i.e., clusters of residues involved directly with binding interactions) is difficult. In the case of hydrophobically mediated interactions, use of hydropathy‐based methods relying on single residue hydrophobicity properties are routinely and widely used to predict propensities for such residues to be present in hydrophobic interfaces. However, recent studies suggest that consideration of hydrophobicity for single residues on a protein surface require accounting of the local environment dictated by neighboring residues and local water. In this study, we use a method derived from percolation theory to evaluate spanning water networks in the first hydration shells of a series of small proteins. We use residue‐based water density and single‐linkage clustering methods to predict hydrophobic regions of proteins; these regions are putatively involved in binding interactions. We find that this simple method is able to predict with sufficient accuracy and coverage the binding interface residues of a series of proteins. The approach is competitive with automated servers. The results of this study highlight the importance of accounting of local environment in determining the hydrophobic nature of individual residues on protein surfaces. Proteins 2014; 82:3312–3326. © 2014 Wiley Periodicals, Inc.     

Exploring permeability of Escherichia coli competence using quantum dots as fluorescent probes

Though people had recognized the pivotal function of CaCl(2) during DNA transformation into Escherichia coli, the mechanism of divalent Ca(2+) cation inducing E. coli competence development is still unknowable. Quantum dots (QDs), as a new fluorescent probe, being applied in biology research, had aroused great interest. We explored the penetrability of E. coli competent cells membrane using QDs and proved directly that competent cells were more permeable than that of noncompetent. The results are significant on understanding the problems of the microbiological genetics.     

氨基酰化酶中金属锌离子的功能作用

 氨基酰化酶是含锌金属酶。该酶每摩尔蛋白中含2摩尔Zn(Ⅱ)离子。金属鳌合剂与酶作用,通过竞争螯合Zn(Ⅱ)离子使酶活力下降。残余活力与残留金属含量呈正相关。竞争螯合的结果,生成不含金属的脱辅基酶蛋白,并导致酶活力的丧失。脱辅基酶由于加入Zn(Ⅱ)离子而恢复其活力。实验表明金属锌离子是氨基酰化酶催化活力所必需。与Zn(Ⅱ)离子相似,Co(Ⅱ)离子也可与脱辅基酶相结合并使之复活。 在190—240nm区域内对比了天然酶、脱辅基酶蛋白与Co(Ⅱ)置换氨基酰化酶的圆二色谱。远紫外圆二色谱表明,与天然酶相比,在脱辅基酶中由于金属离子的丧失导致主链构象发生变化,其中α螺旋增加约7％。因而锌离子(钴离子)对蛋白主链的反应最适构象有一定的稳定作用。脱辅基酶与Co(Ⅱ)离子结合,酶的主链构象恢复至与天然酶几近相同。可认为这是促使酶复活的内在因素。     

Conformational changes and inactivation of rabbit muscle creatine kinase in dimethyl sulfoxide solutions.

The effects of dimethyl sulfoxide (DMSO) on creatine kinase (CK) conformation and enzymatic activity were studied by measuring activity changes, aggregation, and fluorescence spectra. The results showed that at low concentrations (< 65% v/v), DMSO had little effect on CK activity and structure. However, higher concentrations of DMSO led to CK inactivation, partial unfolding, and exposure of hydrophobic surfaces and thiol groups. DMSO caused aggregation during CK denaturation. A 75% DMSO concentration induced the most significant aggregation of CK. The CK inactivation and unfolding kinetics were single phase. The unfolding of CK was an irreversible process in the DMSO solutions. The results suggest that to a certain extent, an enzyme can maintain catalytic activity and conformation in water-organic mixture environments. Higher concentrations of DMSO affected the enzyme structure but not its active site. Inactivation occurred along with noticeable conformational change during CK denaturation. The inactivation and unfolding of CK in DMSO solutions differed from other denaturants such as guanidine, urea, and sodium dodecyl sulfate. The exposure of hydrophobic surfaces was a primary reason for the protein aggregation.     

Molecular Identification and Diversity of ‘Candidatus Phytoplasma solani’ Associated with Red‐leaf Disease of Salvia miltiorrhiza in China

Reddening disease has recently been threatening Salvia miltiorrhiza in China, ranging from 30 to 50%. The main symptoms observed, such as plant stunting, inflorescence malformation, leaf reddening, fibrous roots browning, skin blackening and eventually root rot, are typically associated with phytoplasma infection. The presence of phytoplasmas was demonstrated through phytoplasma‐specific PCR, with the expected amplification (1.8 kb) from symptomatic S. miltiorrhiza plants from Shangluo, Shangzhou and Luonan fields in Shaanxi Province of China. The sequences of 16S rRNA, tuf, secY and vmp1 genes amplified from LN‐1 phytoplasma shared the closest homologies of 99%, 100%, 99% and 98% with those of the reference strain Candidatus Phytoplasma solani (subgroup 16SrXII‐A), respectively. The phylogenetic trees showed that LN‐1 phytoplasma clustered with the members of 16SrXII‐A group, including Ca. P. solani. Computer‐simulated restriction fragment length polymorphism analysis further supported this classification. Diversity analysis showed that all ‘Ca. P. solani’ strains identified from the three different regions examined shared 100% identical 16S rRNA, tuf, secY and vmp1 nucleotide sequences. To the best of our knowledge, this is the first report of phytoplasma infecting the medicinal plant of S. miltiorrhiza. The results demonstrate that ‘Ca. P. solani’ is the presumptive aetiological agent of S. miltiorrhiza reddening disease in China.     

Immunohistochemical localization of irisin in skin,eye, and thyroid and pineal glands of the crested porcupine (Hystrix cristata)

Irisin was first identified in muscle cells. We detected irisin immunoreactivity in various organs of the crested porcupine (Hystrix cristata). In the epidermis, irisin immunoreactivity was localized mainly in stratum basale, stratum spinosum and stratum granulosum layers; immunoreactivity was not observed in the stratum corneum. In the dermis, irisin was found in the external and internal root sheath, cortex and medulla of hair follicles, and in sebaceous glands. Irisin immunoreactivity was found in the neural retina and skeletal muscle fibers associated with the eye. The pineal and thyroid glands also exhibited irisin immunoreactivity.