Molecular characteristics of the <Emphasis Type="Italic">SLA-2</Emphasis> gene from Chinese Hebao pigs

To study the molecular characteristics of swine leukocyte antigen (SLA) class I from the Hebao pig, a rare inbreed in China, a pair of primers was designed to amplify the SLA-2 gene (SLA-2-HB) and then the molecular characteristics of the gene were analyzed by computer. After cloning, sequencing and computer analysis, four SLA-2-HB alleles were found, all of 1119 bp. Sites 3–1097 were an open reading frame encoding 364 amino acids with two sets of intra-chain disulfide bonds comprising four cysteines situated in sites 125, 188, 227 and 283. By alignment of SLA-2-HB sequences with other SLA-2 alleles in the DNA Data Bank of Japan/European Molecular Biology Laboratory/GenBank database, nine key variable amino acid sites were found in the extracellular domain of the SLA-2-HB alleles at sites 23(F), 24(I), 43(A), 44(K), 50(Q), 73(N), 95(I), 114(R) and 216(S), which could be used to differentiate other SLA-2 alleles. The amino acid identities between SLA-2-HB and other SLA-2, SLA-3 and SLA-1 alleles were 87.1–97.0%, 85.0–93.9% and 83.3–88.6%, respectively. The phylogenetic tree of SLA-2-HB showed that it was relatively independent of the other SLA-2 genes. Furthermore, the SLA-2-HB alleles were similar to HLA-B15 and HLA-A2 functional domains and preserved some functional sites of HLA-A2. It was concluded that SLA-2-HB is an allele of SLA-2 and that the Hebao pig might have evolved independently in China.     

RNT4 3'-UTR insertion/deletion polymorphisms are not associated with atrial septal defect in Chinese Han population: a brief communication

Atrial septal defect (ASD) is a common type of congenital heart disease, which is defined as any communication through atrial septum. Several studies have revealed that genetic factors may influence the susceptibility of ASD. Recent studies have shown that reticulon 4 (RTN4) gene might be involved in some processes relevant to heart development, such as regulation of cell migration and vascular remodeling. This study aimed to evaluate RTN4 gene polymorphisms of CAA and TATC insertion/deletion in relation to the risk of ASD in Chinese Han population. A total of 175 ASD patients and 308 unrelated healthy controls were successfully investigated. The polymorphisms of patients were determined by polymerase chain reaction-polyacrylamide gel electrophoresis. There was no significant difference in the allele frequencies of CAA and TATC insertion/deletion in RNT4 gene between ASD patients and controls. The same results were seen in their genotypes. The present study suggests that CAA and TATC insertion/deletion polymorphisms of RNT4 gene may not be a useful marker to predict the susceptibility of ASD in Chinese Han population.     

Ethanol-induced yeast flocculation directed by the promoter of TPS1 encoding trehalose-6-phosphate synthase 1 for efficient ethanol production

Yeast flocculation is an important trait in the brewing industry as well as in ethanol production, through which biomass can be recovered by cost-effective sedimentation. However, mass transfer limitation may affect yeast growth and ethanol fermentation if the flocculation occurs earlier before fermentation is completed. In this article, a novel type of cell-cell flocculation induced by trehalose-6-phosphate synthase 1 (TPS1) promoter was presented. The linear cassette HO-P(TPS1)-FLO1(SPSC01)-KanMX4-HO was constructed to transform the non-flocculating industrial yeast S. cerevisiae 4126 by chromosome integration to obtain a new flocculating yeast strain, ZLH01, whose flocculation was induced by ethanol produced during fermentation. The experimental results illustrated that flocculation of ZLH01 was triggered by 3% (v/v) ethanol and enhanced as ethanol concentration increased till complete flocculation was achieved at ethanol concentration of 8% (v/v). Real time PCR analysis confirmed that the expression of FLO1(SPSC01) was dependent on ethanol concentration. The growth and ethanol fermentation of ZLH01 were improved significantly, compared with the constitutive flocculating yeast BHL01 engineered with the same FLO gene but directed by the constitutive 3-phosphoglycerate kinase promoter PGK1, particularly under high temperature conditions. These characteristics make the engineered yeast more suitable for ethanol production from industrial substrates under high gravity and temperature conditions. In addition, this strategy offers advantage in inducing differential expression of other genes for metabolic engineering applications of S. cerevisiae.     

Cell Therapy: A Safe and Efficacious Therapeutic Treatment for Alzheimer��s Disease in APP+PS1 Mice

Previously, our lab was the first to report the use of antigen-sensitized dendritic cells as a vaccine against Alzheimer’s disease (AD). In preparation of this vaccine, we sensitized the isolated dendritic cells ex vivo with Aβ peptide, and administered these sensitized dendritic cells as a therapeutic agent. This form of cell therapy has had success in preventing and/or slowing the rate of cognitive decline when administered prior to the appearance of Aβ plaques in PDAPP mice, but has not been tested in 2×Tg models. Herein, we test the efficacy and safety of this vaccine in halting and reversing Alzheimer’s pathology in 9-month-old APP+PS1 mice. The results showed that administration of this vaccine elicits a long-lasting antibody titer, which correlated well with a reduction of Aβ burden upon histological analysis. Cognitive function in transgenic responders to the vaccine was rescued to levels similar to those found in non-transgenic mice, indicating that the vaccine is capable of providing therapeutic benefit in APP+PS1 mice when administered after the onset of AD pathology. The vaccine also shows indications of circumventing past safety problems observed in AD immunotherapy, as Th1 pro-inflammatory cytokines were not elevated after long-term vaccine administration. Moreover, microhemorrhaging and T-cell infiltration into the brain are not observed in any of the treated subjects. All in all, this vaccine has many advantages over contemporary vaccines against Alzheimer’s disease, and may lead to a viable treatment for the disease in the future.     

Theoretical investigation of the radical scavenging activity of shikonin and acylshikonin derivatives

The radical scavenging activity of shikonin and acylshikonin derivatives was studied by using density functional theory. The hydrogen bond property of the studied structures was investigated using the atoms in molecules (AIM) theory. It turned out that the hydrogen bond is important for good radical scavenging activity. The hydrogen atom transfer for shikonin and acylshikonin derivatives is difficult to obtain because of the high bond dissociation energy (BDE). However, shikonin and acylshikonin derivatives appear to be good candidates for the one-electron-transfer. The introduction of acyl groups for shikonin decreases the ionization potential (IP) values compared with that of shikonin. The acylshikonin derivatives with 1H-pyrrole, furan, and thiophene groups are expected to be of the highest radical scavenging activity among the compounds investigated in this study. Taking this system as an example, we present an efficient method for the investigation of radical scavenging activity from theoretical point of view.     

Crucial Involvement of Tumor-Associated Neutrophils in the Regulation of Chronic Colitis-Associated Carcinogenesis in Mice

Ulcerative colitis (UC) is a major form of chronic inflammation that can frequently progress to colon cancer. Several studies have demonstrated massive infiltration of neutrophils and macrophages into the lamina propria and submucosa in the progression of UC-associated colon carcinogenesis. Macrophages contribute to the development of colitis-associated colon cancer (CAC). However, the role of neutrophils is not well understood. To better understand the involvement of tumor-associated neutrophils (TANs) in the regulation of CAC, we used a mouse CAC model produced by administering azoxymethane (AOM), followed by repeated dextran sulfate sodium (DSS) ingestion. This causes severe colonic inflammation and subsequent development of multiple tumors in mice colon. We observed that colorectal mucosal inflammation became increasingly severe with AOM and DSS treatment. Macrophages infiltrated the lamina propria and submucosa, together with a marked increase in neutrophil infiltration. The chemokine CXCL2 increased in the lamina propria and submucosal regions of the colons of the treated mice, together with the infiltration of neutrophils expressing CXCR2, a specific receptor for CXCL2. This process was followed by neoplastic transformation. After AOM and DSS treatment, the mice showed enhanced production of metalloproteinase (MMP)-9 and neutrophil elastase (NE), accompanied by excessive vessel generation and cell proliferation. Moreover, CXCL2 promoted neutrophil recruitment and induced neutrophils to express MMP-9 and NE in vitro. Furthermore, administration of neutrophil-neutralizing antibodies after the last DSS cycle markedly reduced the number and size of tumors and decreased the expression of CXCR2, CXCL2, MMP-9, and NE. These observations indicate a crucial role for TANs in the initiation and progression of CAC and suggest that the CXCL2–CXCR2 axis might be useful in reducing the risk of UC-associated colon cancer.     

Strong activation of cyclooxygenase I and II catalytic activity by dietary bioflavonoids

Cyclooxygenases (COXs) catalyze the conversion of arachidonic acid to prostaglandins (PGs), thromboxanes, and hydroxyeicosatetraenoic acids. In the present study, we investigated several dietary bioflavonoids for their ability to modulate the catalytic activity of COX I and II in vitro and also in cultured cells. We found that some of them are the most powerful direct stimulators of the catalytic activity of COX I and II known to date, increasing the formation of prostaglandin products in vitro by up to 11-fold over the controls. This stimulatory effect of bioflavonoids is enzyme specific because none of them stimulates the catalytic activity of a number of lipooxygenases tested. Compared with phenol, a prototypical COX stimulator commonly used in vitro, the naturally occurring bioflavonoids are up to 29 times more efficacious in stimulating the COX activity. Additional studies using intact cells in culture showed that some of the dietary compounds that were active in the biochemical assays also activated the formation of PGE(2) (a representative PG) when they were present at 0.01 to 1 muM concentrations. The stimulatory effect of dietary compounds on COX-mediated PG formation is far more potent in intact cells than in the in vitro assays. Mechanistically, bioflavonoids mainly acted to slow down the suicidal inactivation of the COX enzymes, but they did not appear to reactivate the inactivated enzymes. The finding of this study suggests that some of the bioflavonoids likely will serve as the naturally occurring cofactors for the COX enzymes in humans.     

Lineage-Specific Domain Fusion in the Evolution of Purine Nucleotide Cyclases in Cyanobacteria

Cyclic nucleotides (both cAMP and cGMP) play extremely important roles in cyanobacteria, such as regulating heterocyst formation, respiration, or gliding. Catalyzing the formation of cAMP and cGMP from ATP and GTP is a group of functionally important enzymes named adenylate cyclases and guanylate cyclases, respectively. To understand their evolutionary patterns, in this study, we presented a systematic analysis of all the cyclases in cyanobacterial genomes. We found that different cyanobacteria had various numbers of cyclases in view of their remarkable diversities in genome size and physiology. Most of these cyclases exhibited distinct domain architectures, which implies the versatile functions of cyanobacterial cyclases. Mapping the whole set of cyclase domain architectures from diverse prokaryotic organisms to their phylogenetic tree and detailed phylogenetic analysis of cyclase catalytic domains revealed that lineage-specific domain recruitment appeared to be the most prevailing pattern contributing to the great variability of cyanobacterial cyclase domain architectures. However, other scenarios, such as gene duplication, also occurred during the evolution of cyanobacterial cyclases. Sequence divergence seemed to contribute to the origin of putative guanylate cyclases which were found only in cyanobacteria. In conclusion, the comprehensive survey of cyclases in cyanobacteria provides novel insight into their potential evolutionary mechanisms and further functional implications.