General Information

A novel cDNA clone encoding a COR413-like gene was isolated by suppression subtraction hybridization and cDNA library screening from sea-island cotton (Gossypium barbadense). This gene (designated as GbCOR413, Accession number: AY761065) has a total length of 893 bp with an open reading frame of 600 bp, encoding a predicated polypeptide of 200 amino acids with a molecular weight of 22.74 kDa and a predicated pI of 9.2. Bioinformatics analyses revealed that this gene belonged to a novel stress-regulated multi-spanning transmembrane protein family without signal peptide. By means of semi-quantities RT-PCR analysis, the expression of GbCOR413 under short-term cold treatment at 4°C, water submergence and abscic acid treatment was investigated. Our studies suggested that the cloned gene was a new member of COR gene family which was slowly responsive to cold stress in cotton. Jin Wang and Kai-Jing Zuo are co-first authors of this paper.     

Thermodynamics of nucleosomal core particles

In this paper, a numerically detailed thermodynamic investigation of nucleosomal core particles is presented. The nonlinear Poisson-Boltzmann equation governs the electrostatic properties of both the DNA and histone protein. Brownian dynamics is used as the leading method, in combination with the analysis of the electrical features of the nucleosome. At elevated temperature, the structure of the nucleosome is destabilized by the decrease in electrical interactions of DNA-histone complexes, which can be explained with the EDL theory. Two obvious unwrapping transitions can be found, occurring within the temperature ranges 43-52 and 65-80 degrees C. The first transition is characterized by the melting of DNA terminal domains, and the feature of the second transition is the massive unwrapping of the DNA middle domain. It can be concluded that the nucleosomal DNA consists of two distinct structures, where the DNA terminal domains are less tightly bound to the histone than the DNA middle domain.     

Involvement of sphingoid bases in mediating reactive oxygen intermediate production and programmed cell death in Arabidopsis

Sphingolipids have been suggested to act as second messengers for an array of cellular signaling activities in plant cells, including stress responses and programmed cell death （PCD）. However, the mechanisms underpinning these processes are not well understood. Here, we report that an Arabidopsis mutant, fumonisin B1 r_esistant11-1 （/br11-1）, which fails to generate reactive oxygen intermediates （ROIs）, is incapable of initiating PCD when the mutant is challenged by fumonisin B l （FB0, a specific inhibitor of ceramide synthase. Molecular analysis indicated that FBR11 encodes a long-chain base 1 （LCB 1） subunit of serine palmitoyltransferase （SPT）, which catalyzes the first rate-limiting step of de novo sphingolipid synthesis. Mass spectrometric analysis of the sphingolipid concentrations revealed that whereas the fbr11-1 mutation did not affect basal levels of sphingoid bases, the mutant showed attenuated formation of sphingoid bases in response to FBl. By a direct feeding experiment, we show that the free sphingoid bases dihydrosphingosine, phytosphingosine and sphingosine efficiently induce ROI generation followed by cell death. Conversely, ROI generation and cell death induced by dihydrosphingosine were specifically blocked by its phosphorylated form dihydrosphingosine- 1-phosphate in a dosedependent manner, suggesting that the maintenance of homeostasis between a free sphingoid base and its phosphorylated derivative is critical to determining the cell fate. Because alterations of the sphingolipid level occur prior to the ROI production, we propose that the free sphingoid bases are involved in the control of PCD in Arabidopsis, presumably through the regulation of the ROI level upon receiving different developmental or environmental cues.     

Crystal structure of RNase T, an exoribonuclease involved in tRNA maturation and end turnover

The 3' processing of most bacterial precursor tRNAs involves exonucleolytic trimming to yield a mature CCA end. This step is carried out by RNase T, a member of the large DEDD family of exonucleases. We report the crystal structures of RNase T from Escherichia coli and Pseudomonas aeruginosa, which show that this enzyme adopts an opposing dimeric arrangement, with the catalytic DEDD residues from one monomer closely juxtaposed with a large basic patch on the other monomer. This arrangement suggests that RNase T has to be dimeric for substrate specificity, and agrees very well with prior site-directed mutagenesis studies. The dimeric architecture of RNase T is very similar to the arrangement seen in oligoribonuclease, another bacterial DEDD family exoribonuclease. The catalytic residues in these two enzymes are organized very similarly to the catalytic domain of the third DEDD family exoribonuclease in E. coli, RNase D, which is monomeric.     

Culture and neural differentiation of rat bone marrow mesenchymal stem cells in vitro

Adult bone marrow mesenchymal stem cells (MSCs) can differentiate into several types of mesenchymal cells, including osteocytes, chondrocytes, and adipocytes, but can also differentiate into non-mesenchymal cells, such as neural cells, under appropriate experimental conditions. Until now, many protocols for inducing neuro-differentiation in MSCs in vitro have been reported. But due to the differences in MSCs' isolation and culture conditions, the results of previous studies lacked consistency and comparability. In this study, we induced differentiation into neural phenotype in the same MSCs population by three different treatments: beta-mercaptoethanol, serum-free medium and co-cultivation with fetal mouse brain astrocytes. In all of the three treatments, MSCs could express neural markers such as NeuN or GFAP, associating with remarkable morphological modifications. But these treatments led to neural phenotype in a non-identical manner. In serum-free medium, MSCs mainly differentiated into neuron-like cells, expressing neuronal marker NeuN, and BME can promote this process. Differently, after co-culturing with astrocytes, MSCs leaned to differentiate into GFAP(+) cells. These data confirmed that MSCs can exhibit plastic neuro-differentiational potential in vitro, depending on the protocols of inducement.     

A novel approach to sequence validating protein expression clones with automated decision making

Background  

Whereas the molecular assembly of protein expression clones is readily automated and routinely accomplished in high throughput, sequence verification of these clones is still largely performed manually, an arduous and time consuming process. The ultimate goal of validation is to determine if a given plasmid clone matches its reference sequence sufficiently to be "acceptable" for use in protein expression experiments. Given the accelerating increase in availability of tens of thousands of unverified clones, there is a strong demand for rapid, efficient and accurate software that automates clone validation.     

The Effect of α7nAChR Signaling on T Cells and Macrophages and Their Clinical Implication in the Treatment of Rheumatic Diseases

Neurochemical Research - Rheumatoid arthritis (RA) is one of the most common autoimmune disease and until now, the etiology and pathogenesis of RA is not fully understood, although dysregulation of...     

Long Non-coding RNA ANRIL Downregulation Alleviates Neuroinflammation in an Ischemia Stroke Model via Modulation of the miR-671-5p/NF-κB Pathway

Neurochemical Research - The aim of this study was to investigate the role and underlying mechanism of the long non-coding RNA ANRIL (antisense noncoding RNA in the INK4 locus, ANRIL) in ischemia...