Drosophila ORC specifically binds to ACE3, an origin of DNA replication control element

In the yeast Saccharomyces cerevisiae, sequence-specific DNA binding by the origin recognition complex (ORC) is responsible for selecting origins of DNA replication. In metazoans, origin selection is poorly understood and it is unknown whether specific DNA binding by metazoan ORC controls replication. To address this problem, we used in vivo and in vitro approaches to demonstrate that Drosophila ORC (DmORC) binds to replication elements that direct repeated initiation of replication to amplify the Drosophila chorion gene loci in the follicle cells of egg chambers. Using immunolocalization, we observe that ACE3, a 440-bp chorion element that contains information sufficient to drive amplification, directs DmORC localization in follicle cells. Similarly, in vivo cross-linking and chromatin immunoprecipitation assays demonstrate association of DmORC with both ACE3 and two other amplification control elements, AER-d and ACE1. To demonstrate that the in vivo localization of DmORC is related to its DNA-binding properties, we find that purified DmORC binds to ACE3 and AER-d in vitro, and like its S. cerevisiae counterpart, this binding is dependent on ATP. Our findings suggest that sequence-specific DNA binding by ORC regulates initiation of metazoan DNA replication. Furthermore, adaptation of this experimental approach will allow for the identification of additional metazoan ORC DNA-binding sites and potentially origins of replication.     

Relationship of Yersinia pseudotuberculosis O antigens IA,IIA, and IVB: the IIA gene cluster was derived from that of IVB

O antigen is part of the lipopolysaccharide present in the outer membrane of gram-negative bacteria and is highly polymorphic. In this study, we obtained sequences of the O-antigen gene clusters for the Yersinia pseudotuberculosis antigens IA, IIA, and IVB. We propose that the IIA gene cluster was derived from the IVB cluster, one of the very few cases in which a parent gene cluster is identified, and that the IA gene cluster could be a hybrid of the IVB and IB gene clusters. All three O antigens contain 6-deoxy-D-mannoheptose, and we identified six genes for the biosynthetic pathway for the precursor of this sugar, GDP-6-deoxy-D-mannoheptose.     

A Strongly CD34-Positive Meningioma that was Difficult to Distinguish from a Solitary Fibrous Tumor

Abstract

Fibrous or transitional meningioma and solitary fibrous tumor (SFT) are frequently difficult to differentiate from each other on the basis of histopathology. It is extremely unusual for a meningioma to exhibit diffuse, strongly positive immunoreactivity for cluster of differentiation 34 (CD34), and this has never been previously reported from a histopathological specimen. A patient with transitional meningioma that exhibited strongly positive for CD34, which has been regarded as characteristic of SFT and is considered to be useful for distinguishing the latter from meningioma, is reported.     

Experimental evidence that mutated-self peptides derived from mitochondrial DNA somatic mutations have the potential to trigger autoimmunity

Autoimmune disease is a critical health concern, whose etiology remains enigmatic. We hypothesized that immune responses to somatically mutated self proteins could have a role in the development of autoimmune disease. IFN-γ secretion by T cells stimulated with mitochondrial peptides encoded by published mitochondrial DNA was monitored to test the hypothesis. Human peripheral blood mononuclear cells (PBMCs) of healthy controls and autoimmune patients were assessed for their responses to the self peptides and mutated-self peptides differing from self by one amino acid. None of the self peptides but some of the mutated-self peptides elicited an immune response in healthy controls. In some autoimmune patients, PBMCs responded not only to some of the mutated-self peptides, but also to some of the self peptides, suggesting that there is a breach of self-tolerance in these patients. Although PBMCs from healthy controls failed to respond to self peptides when stimulated with self, the mutated-self peptide could elicit a response to the self peptide upon re-stimulation in vitro, suggesting that priming with mutated-self peptides elicits a cross-reactive response with self. The data raise the possibility that DNA somatic mutations are one of the events that trigger and/or sustain T cell responses in autoimmune diseases.     

The generation and characterization of a cell line derived from a sporadic renal angiomyolipoma: use of telomerase to obtain stable populations of cells from benign neoplasms

Angiomyolipomas are benign tumors of the kidney derived from putative perivascular epithelioid cells, that may undergo differentiation into cells with features of melanocytes, smooth muscle, and fat. To gain further insight into angiomyolipomas, we have generated the first human angiomyolipoma cell line by sequential introduction of SV40 large T antigen and human telomerase into human angiomyolipoma cells. These cells show phenotypic characteristics of angiomyolipomas, namely differentiation markers of smooth muscle (smooth muscle actin), adipose tissue (peroxisome proliferator-activator receptor gamma, PPARgamma), and melanocytes (microophthalmia, MITF), thus demonstrating that a single cell type can exhibit all of these phenotypes. These cells should serve as a valuable tool to elucidate signal transduction pathways underlying renal angiomyolipomas.     

Urticaria from beer: an immediate hypersensitivity reaction due to a 10-kDa protein derived from barley

BACKGROUND: Urticaria from beer has been reported in atopic patients. In these subjects, the skin-prick test positivity to and presence of specific serum immunoglobulin (Ig)E for barley malt, the basic ingredient used in brewing, suggested a type I hypersensitivity to barley component(s). OBJECTIVE: To identify the beer allergen(s) and to investigate the presence of related proteins in barley. METHODS: Three patients with urticaria from beer and other atopic people, some of them suffering from baker's asthma, were examined for both prick test sensitivity to and the occurrence of serum-specific IgE for partially purified proteins from beer. Allergen identification in beer, malt and barley was performed by immunoblotting. RESULTS: Skin-prick tests and detection of specific IgE by both solid-phase (RAST) and liquid-phase (AlaSTAT) assays demonstrated that the 5-20-kDa beer protein fraction contained the allergen. Immunoblot analysis with sera of patients with urticaria from beer showed that IgE bound only the 10-kDa protein band in beer and malt, whereas a main 16-kDa protein was revealed in barley in addition to a very faint 10-kDa band. With the serum of a patient suffering from baker's asthma no IgE binding bands were observed in beer, whereas specific IgE binding to several proteins, including a major 16-kDa component, were detected for both malt and barley. CONCLUSIONS: Urticaria from beer is an IgE-mediated hypersensitivity reaction induced by a protein component of approximately 10 kDa deriving from barley. This allergen does not seem to be related to the major barley 16-kDa allergen responsible for baker's asthma. Because of the severity of the allergic manifestations to beer we recommend testing atopic patients positive to malt/barley and/or who exhibit urticarial reactions after drinking beer for their sensitivity to this beverage.     

Application of the library least-squares analysis to whole-body counter spectra derived from an array of detectors

The library least-squares method was applied to the analysis of gamma-ray spectra obtained from an array of 54 NaI(T1) detectors in a whole-body counter. The analysis of spectra which were obtained over a period of 8 yr demonstrates the applicability of the method despite inherent variations encountered in large counting systems. The elements of interest analyzed were total-body K, Ca, Na, Cl, and P. Least-squares fits obtained with library standards derived from distributed sources were better than those obtained from library standards derived from localized sources.     

Chromosome fragmentation resulting from an inability to repair transposase-induced DNA double-strand breaks in PCNA mutants of Drosophila

Proliferating cell nuclear antigen (PCNA) has several rolesin progression through S phase: it is required for the functionof DNA polymerases     

Human monoclonal antibody derived from an autoimmune thrombocytopenic purpura patient, recognizing an intermediate filament's determinant common to vimentin and desmin.

Human monoclonal antibody (mAb) technology has been helpful in identifying autoantibodies that are involved in various autoimmune disorders. We report here the results of such an attempt to immortalize antibody-forming cells from spleen of an autoimmune thrombocytopenic purpura (ATP) patient and characterize the resulting mAb. The human mAb we derived, denoted (4G9), binds to the cytoskeletal network. Using immunofluorescence analyses of permeabilized and fixed cell lines and tissues, the 4G9 mAb was shown to be anti-vimentin specific by virtue of its intracellular staining pattern, decoration of cell lines of mesenchymal (but not epithelial) origin, and by the fact that polyclonal anti-vimentin (and not anti-actin, prekeratin, tubulin or vinculin) antibodies inhibited its binding to intermediate filaments of a fibroblastoid cell line. The presence of vimentin in platelets was also confirmed in the present study by immunoblotting of platelet extract using murine anti-vimentin mAb. Interestingly, in addition to vimentin the 4G9 mAb decorated intermediate filaments in desmin-expressing muscular cells, suggesting that the 4G9 epitope is most likely located within the homologous sequences that are known to be shared between vimentin and desmin.     

The transplantation of mesenchymal stem cells derived from unconventional sources: an innovative approach to multiple sclerosis therapy

In recent years, in the effort to find a potential innovative therapy for multiple sclerosis (MS), researchers focused on transplantation of mesenchymal stem cells (MSCs) due to their well-recognized ability to suppress inflammatory/autoimmune responses and exert neuroregenerative properties. MSCs are a heterogeneous subset of pluripotent non-hematopoietic stromal cells that can be isolated from many different adult tissues, characterized by the capability to differentiate into various cell lineages, and to translocate into damaged areas, providing immunomodulatory effects. To date, several encouraging results were obtained mainly from the use of MSCs derived from the bone marrow (BM-MSCs) in experimental models of MS as well as in clinical trials. However, their use in clinic is limited due to the invasive collecting procedure and the low yield of viable stem cells. Consequently, these restrictions have prompted researchers to look for alternative tissue sources for stem cells such as adipose tissue, fetal annexes, and dental tissues that could represent a novel therapeutic option for MS treatment. Here, we provide an overview of the current knowledge about the most explored BM-MSCs in MS treatment in experimental and clinical studies. Moreover, we propose that unconventional sources of stem cells, which show characteristics similar to that of BM-MSCs, and being less invasive for removal, could be considered an excellent alternative to BM-MSCs and thus could be a promising innovative approach for MS treatment.

     

Phylogenetic analyses of an isolate obtained from potato in 1985 revealed potato virus X was introduced to China via multiple events

Potato virus X (PVX) is one of the most common plant viruses that cause great economic losses to solanaceous plants. We have previously reported the complete genomic sequence of the 2006 Chinese potato isolate FX21 and demonstrated that PVX isolates cluster into two groups: Eurasia and America. Here, we present the complete genomic sequence of one PVX isolate collected from potato in 1985 (PVX-1985). The genome of PVX-1985 is identical to that of FX21 in length and has the same genomic structure. PVX-1985, which like FX21 fell within the Eurasia group, clustered together with isolates from Europe, whereas FX21 clustered together with isolates of primarily Asian origin. Phylogenetic analyses of the complete genomic sequences and of CP gene sequences showed that Chinese PVX isolates have different origins and were introduced via multiple events. Though all the open reading frames of PVX are under negative/purifying selection, the central region of RNA-dependent RNA polymerase is under positive/diversifying selection.     

A case of autoimmune hepatitis needed to be differentiated from EBV hepatitis, in that the histology of liver biopsy specimen was useful for diagnosis]

A 10-year-old girl with autoimmune hepatitis (AIH) was reported. She was admitted to our hospital because of cholestasis and elevation of liver enzymes for 2 months. Laboratory examination revealed that EBV-DNA copy number in the PBMNC (peripheral mononuclear cells) was 1.2 x 10(3) copies/microg of DNA, hypergammaglobulinemia, and positive antinuclear antibody, positive anti-smooth muscle antibody. The histology of her liver biopsy specimen revealed interface hepatitis, dense mononuclear cell infiltrates, mild fibrosis, and negative for EBV in situ hybridization assay indicating AIH and not EBV-associated hepatitis. She was treated firstly with methylprednisolone pulses, then will prednisolone p.o.+azathioprine p.o.. Intravenous cyclophosphamide pulse therapy was introduced because of her abnormal immune pathology. All abnormal laboratory parameters improved to normal levels within 2 months, and EBV-DNA copy number in the PBMNC became negative after 4 months. The histology of liver biopsy specimen was useful for the diagnosis of AIH in such a difficult case needed to be differentiated from EBV hepatitis.