Stacking order, interaction, and weak surface magnetism in layered graphene sheets

published_or_final_versio

Genetic diversity among Toxoplasma gondii isolates from different hosts and geographical locations revealed by analysis of ROP13 gene sequences

Toxoplasma gondii can infect almost all the warm-blooded animals and human beings, causing serious public health problems and economic losses worldwide. Rhoptry protein 13 (ROP13) plays some roles in the invasion process of T. gondii. In this study, sequence variation in ROP13 gene among 14 T. gondii isolates from different geographical locations and hosts was examined. The ROP13 gene was amplified from individual isolates and sequenced. Results show that the length of the ROP13 sequences was 1203 bp. In total, there were 44 variable nucleotide positions in the ROP13 sequences, and sequence variations were 0.1 to 2.0% among the 14 examined T. gondii isolates, representing higher rate in transversion than in transition. Intra-specific nucleotide variations were mainly at the second codon positions. Phylogenetic analysis of the 14 examined T. gondii isolates indicate that the ROP13 sequence was not a suitable genetic marker to differentiate T. gondii isolates of different genotypes from different hosts and geographical regions. Low variation in ROP13 gene sequence may suggest that ROP13 gene could represent a good vaccine candidate against toxoplasmosis.Key words: Toxoplasma gondii, toxoplasmosis, rhpotry protein 13 (ROP13), sequence variation, phylogenetic analysis

Sequence variation in TgROP7 gene among Toxoplasma gondii isolates from different hosts and geographical regions

Toxoplasma gondii can infect a wide range of hosts including mammals and birds, causing toxoplasmosis which is one of the most common parasitic zoonoses worldwide. The present study examined sequence variation in rhoptry 7 (ROP7) gene among different T. gondii isolates from different hosts and geographical localities. Phylogenetic analysis of the examined T. gondii isolates was conducted using the maximum likelihood (ML) method. Sequence analysis revealed that 60 nucleotide positions were variable in the ROP7 gene sequences among the 19 examined T. gondii isolates, corresponding to sequence variations of 0 to 1.7%, which occurred at the first, second and third codons. Phylogenetic analysis indicated that sequence variation in ROP7 gene was low among the examined T. gondii isolates from different hosts and geographical localities, and that the ROP7 sequence was not suitable as genetic marker for the differentiation of T. gondii isolates. The results of the present study suggest that ROP7 gene may be a suitable vaccine candidate.Key words: Sequence variation, rhoptry 7 (ROP7) gene, Toxoplasma gondii, toxoplasmosis, phylogenetic analysis

Calpain-mediated cleavage generates a ZBTB18 N-terminal product that regulates HIF1A signaling and glioblastoma metabolism

Proteolytic cleavage is an important post-translational mechanism to increase protein variability and functionality. In cancer, this process can be deregulated to shut off tumor-suppressive functions. Here, we report that in glioblastoma (GBM), the tumor suppressor ZBTB18 is targeted for protein cleavage by the intracellular protease calpain. The N-terminal (Nte) ZBTB18 cleaved fragment localizes to the cytoplasm and thus, is unable to exert the gene expression repressive function of the uncleaved protein. Mass spectrometry (MS) analysis indicates that the Nte ZBTB18 short form (SF) interacts with C-terminal (Cte) binding proteins 1 and 2 (CTBP1/2), which appear to be involved in HIF1A signaling activation. In fact, we show that the new ZBTB18 product activates HIF1A-regulated genes, which in turn lead to increased lipid uptake, lipid droplets (LD) accumulation, and enhanced metabolic activity. We propose that calpain-mediated ZBTB18 cleavage represents a new mechanism to counteract ZBTB18 tumor suppression and increase tumor-promoting functions in GBM cells

AFM, SEM and TEM Studies on Porous Anodic Alumina

Porous anodic alumina (PAA) has been intensively studied in past decade due to its applications for fabricating nanostructured materials. Since PAA’s pore diameter, thickness and shape vary too much, a systematical study on the methods of morphology characterization is meaningful and essential for its proper development and utilization. In this paper, we present detailed AFM, SEM and TEM studies on PAA and its evolvements with abundant microstructures, and discuss the advantages and disadvantages of each method. The sample preparation, testing skills and morphology analysis are discussed, especially on the differentiation during characterizing complex cross-sections and ultrasmall nanopores. The versatility of PAAs is also demonstrated by the diversity of PAAs’ microstructure

Immune-Complex Mimics as a Molecular Platform for Adjuvant-Free Vaccine Delivery

Protein-based vaccine development faces the difficult challenge of finding robust yet non-toxic adjuvants suitable for humans. Here, using a molecular engineering approach, we have developed a molecular platform for generating self-adjuvanting immunogens that do not depend on exogenous adjuvants for induction of immune responses. These are based on the concept of Immune Complex Mimics (ICM), structures that are formed between an oligomeric antigen and a monoclonal antibody (mAb) to that antigen. In this way, the roles of antigens and antibodies within the structure of immune complexes are reversed, so that a single monoclonal antibody, rather than polyclonal sera or expensive mAb cocktails can be used. We tested this approach in the context of Mycobacterium tuberculosis (MTB) infection by linking the highly immunogenic and potentially protective Ag85B with the oligomeric Acr (alpha crystallin, HspX) antigen. When combined with an anti-Acr monoclonal antibody, the fusion protein formed ICM which bound to C1q component of the complement system and were readily taken up by antigen-presenting cells in vitro. ICM induced a strong Th1/Th2 mixed type antibody response, which was comparable to cholera toxin adjuvanted antigen, but only moderate levels of T cell proliferation and IFN-γ secretion. Unfortunately, the systemic administration of ICM did not confer statistically significant protection against intranasal MTB challenge, although a small BCG-boosting effect was observed. We conclude that ICM are capable of inducing strong humoral responses to incorporated antigens and may be a suitable vaccination approach for pathogens other than MTB, where antibody-based immunity may play a more protective role

Cell arrest and cell death in mammalian preimplantation development

The causes, modes, biological role and prospective significance of cell death in preimplantation development in humans and other mammals are still poorly understood. Early bovine embryos represent a very attractive experimental model for the investigation of this fundamental and important issue. To obtain reference data on the temporal and spatial occurrence of cell death in early bovine embryogenesis, three-dimensionally preserved embryos of different ages and stages of development up to hatched blastocysts were examined in toto by confocal laser scanning microscopy. In parallel, transcript abundance profiles for selected apoptosis-related genes were analyzed by real-time reverse transcriptase-polymerase chain reaction. Our study documents that in vitro as well as in vivo, the first four cleavage cycles are prone to a high failure rate including different types of permanent cell cycle arrest and subsequent non-apoptotic blastomere death. In vitro produced and in vivo derived blastocysts showed a significant incidence of cell death in the inner cell mass (ICM), but only in part with morphological features of apoptosis. Importantly, transcripts for CASP3, CASP9, CASP8 and FAS/FASLG were not detectable or found at very low abundances. In vitro and in vivo, errors and failures of the first and the next three cleavage divisions frequently cause immediate embryo death or lead to aberrant subsequent development, and are the main source of developmental heterogeneity. A substantial occurrence of cell death in the ICM even in fast developing blastocysts strongly suggests a regular developmentally controlled elimination of cells, while the nature and mechanisms of ICM cell death are unclear. Morphological findings as well as transcript levels measured for important apoptosis-related genes are in conflict with the view that classical caspase-mediated apoptosis is the major cause of cell death in early bovine development

Differences in carotid arterial morphology and composition between individuals with and without obstructive coronary artery disease: A cardiovascular magnetic resonance study

Objective: We sought to determine differences with cardiovascular magnetic resonance (CMR) in the morphology and composition of the carotid arteries between individuals with angiographically-defined obstructive coronary artery disease (CAD, = 50% stenosis, cases) and those with angiographically normal coronaries (no lumen irregularities, controls). Methods and results: 191 participants (50.3% female; 50.8% CAD cases) were imaged with a multi-sequence, carotid CMR protocol at 1.5T. For each segment of the carotid, lumen area, wall area, total vessel area (lumen area + wall area), mean wall thickness and the presence or absence of calcification and lipid-rich necrotic core were recorded bilaterally. In male CAD cases compared to male controls, the distal bulb had a significantly smaller lumen area (60.0 [plus or minus] 3.1 vs. 79.7 [plus or minus] 3.2 mm[super]2, p less than 0.001) and total vessel area (99.6 [plus or minus] 4.0 vs. 119.8 [plus or minus] 4.1 mm[super]2; p less than 0.001), and larger mean wall thickness (1.25 [plus or minus] 0.03 vs. 1.11 [plus or minus] 0.03 mm; p = 0.002). Similarly, the internal carotid had a smaller lumen area (37.5 [plus or minus] 1.8 vs. 44.6 [plus or minus] 1.8 mm[super]2; p = 0.006) and smaller total vessel area (64.0 [plus or minus] 2.3 vs. 70.9 [plus or minus] 2.4 mm[super]2; p = 0.04). These metrics were not significantly different between female groups in the distal bulb and internal carotid or for either gender in the common carotid. Male CAD cases had an increased prevalence of lipid-rich necrotic core (49.0% vs. 19.6%; p = 0.003), while calcification was more prevalent in both male (46.9% vs. 17.4%; p = 0.002) and female (33.3% vs. 14.6%; p = 0.031) CAD cases compared to controls. Conclusion: Males with obstructive CAD compared to male controls had carotid bulbs and internal carotid arteries with smaller total vessel and lumen areas, and an increased prevalence of lipid-rich necrotic core. Carotid calcification was related to CAD status in both males and females. Carotid CMR identifies distinct morphological and compositional differences in the carotid arteries between individuals with and without angiographically-defined obstructive CAD.Carotid Atherosclerosis (MRI) Progression Study (CAMPS, HL076378) and Cardiovascular Research Training Program (T-32, HL07838); and the General Clinical Research Center at the Wake Forest University School of Medicine (M01 RR-07122)

Morphological changes of injected calcium phosphate cement in osteoporotic compressed vertebral bodies

SUMMARY: This study was undertaken to investigate the radiologic and clinical outcomes of vertebroplasty with calcium phosphate (CaP) cement in patients with osteoporotic vertebral compression fractures. The morphological changes of injected CaP cement in osteoporotic compressed vertebral bodies were variable and unpredictable. We suggest that the practice of vertebroplasty using CaP should be reconsidered. INTRODUCTION: Recently, CaP, an osteoconductive filler material, has been used in the treatment of osteoporotic compression fractures. However, the clinical results of CaP-cement-augmented vertebrae are still not well established. The purpose of this study is to assess the clinical results of vertebroplasty with CaP by evaluating the morphological changes of CaP cement in compressed vertebral bodies. METHODS: Fourteen patients have been followed for more than 2 years after vertebroplasty. The following parameters were reviewed: age, sex, T score, compliance with osteoporosis medications, visual analog scale score, compression ratio, subsequent compression fractures, and any morphological changes in the filler material. RESULTS: The morphological changes of injected CaP included reabsorption, condensation, bone formation (osteogenesis), fracture of the CaP solid hump, and heterotopic ossification. Out of 14 patients, 11 (78.6%) developed progression of the compression of the CaP-augmented vertebral bodies after vertebroplasty. CONCLUSIONS: The morphological changes of the injected CaP cement in the vertebral bodies were variable and unpredictable. The compression of the CaP-augmented vertebrae progressed continuously for 2 years or more. The findings of this study suggest that vertebroplasty using CaP cement should be reconsidered.ope

The Epstein-Barr Virus G-Protein-Coupled Receptor Contributes to Immune Evasion by Targeting MHC Class I Molecules for Degradation

Epstein-Barr virus (EBV) is a human herpesvirus that persists as a largely subclinical infection in the vast majority of adults worldwide. Recent evidence indicates that an important component of the persistence strategy involves active interference with the MHC class I antigen processing pathway during the lytic replication cycle. We have now identified a novel role for the lytic cycle gene, BILF1, which encodes a glycoprotein with the properties of a constitutive signaling G-protein-coupled receptor (GPCR). BILF1 reduced the levels of MHC class I at the cell surface and inhibited CD8+ T cell recognition of endogenous target antigens. The underlying mechanism involves physical association of BILF1 with MHC class I molecules, an increased turnover from the cell surface, and enhanced degradation via lysosomal proteases. The BILF1 protein of the closely related CeHV15 c1-herpesvirus of the Rhesus Old World primate (80% amino acid sequence identity) downregulated surface MHC class I similarly to EBV BILF1. Amongst the human herpesviruses, the GPCR encoded by the ORF74 of the KSHV c2-herpesvirus is most closely related to EBV BILF1 (15% amino acid sequence identity) but did not affect levels of surface MHC class I. An engineered mutant of BILF1 that was unable to activate G protein signaling pathways retained the ability to downregulate MHC class I, indicating that the immune-modulating and GPCR-signaling properties are two distinct functions of BILF1. These findings extend our understanding of the normal biology of an important human pathogen. The discovery of a third EBV lytic cycle gene that cooperates to interfere with MHC class I antigen processing underscores the importance of the need for EBV to be able to evade CD8+ T cell responses during the lytic replication cycle, at a time when such a large number of potential viral targets are expressed