The perinucleolar region represents a special nuclear compartment involved in the cell malignancy and the perinucleolar heterochromatin reflects the presence of silent genes. The present study was undertaken to provide complementary and missing information on the perinucleolar heterochromatin in differentiating neutrophils in the bone marrow of patients with the chronic myeloid leukemia. That lineage is a very convenient model because of the increased number of granulocytic precursors that is satisfactory for size as well as optical density measurements in single cells. Moreover, the differentiation stages of neutrophils are well defined and easily identified. According to diameter measurements the enlarged width of the perinucleolar heterochromatin shell accompanied the decreasing nucleolar size in advanced stages of the cell differentiation. Such trend was not influenced by the anti-leukemic therapy with imatinib. Thus the increasing size of the perinucleolar heterochromatin shell with silent genes might reflect the genomic stability of the perinucleolar region during the cell differentiation. On the other hand, the increased perinucleolar heterochromatin condensation after the specific anti-leukemic therapy with imatinib indicated a “premature terminal differentiation” of leukemic neutrophils.
- MeSH
- Benzamides therapeutic use MeSH
- Cell Differentiation * genetics immunology drug effects MeSH
- Cell Nucleus * genetics microbiology pathology MeSH
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy genetics immunology MeSH
- Heterochromatin * genetics immunology pathology MeSH
- Bone Marrow immunology drug effects MeSH
- Humans MeSH
- Models, Genetic MeSH
- Neutrophils immunology pathology drug effects MeSH
- Piperazines therapeutic use MeSH
- Granulocyte Precursor Cells immunology pathology drug effects MeSH
- Pyrimidines therapeutic use MeSH
- Statistics as Topic MeSH
- Cell Nucleus Structures genetics immunology microbiology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
Amoebae play an important ecological role as predators in microbial communities. They also serve as niche for bacterial replication, harbor endosymbiotic bacteria and have contributed to the evolution of major human pathogens. Despite their high diversity, marine amoebae and their association with bacteria are poorly understood. Here we describe the isolation and characterization of two novel marine amoebae together with their bacterial endosymbionts, tentatively named 'Candidatus Occultobacter vannellae' and 'Candidatus Nucleophilum amoebae'. While one amoeba strain is related to Vannella, a genus common in marine habitats, the other represents a novel lineage in the Amoebozoa. The endosymbionts showed only low similarity to known bacteria (85-88% 16S rRNA sequence similarity) but together with other uncultured marine bacteria form a sister clade to the Coxiellaceae. Using fluorescence in situ hybridization and transmission electron microscopy, identity and intracellular location of both symbionts were confirmed; one was replicating in host-derived vacuoles, whereas the other was located in the perinuclear space of its amoeba host. This study sheds for the first time light on a so far neglected group of protists and their bacterial symbionts. The newly isolated strains represent easily maintainable model systems and pave the way for further studies on marine associations between amoebae and bacterial symbionts.
- MeSH
- Amoeba classification microbiology MeSH
- Cell Nucleus microbiology MeSH
- Cytoplasm microbiology MeSH
- Species Specificity MeSH
- Gammaproteobacteria classification isolation & purification physiology MeSH
- Symbiosis physiology MeSH
- Aquatic Organisms classification isolation & purification microbiology MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Ultrastructural changes induced by Rickettsia slovaca standard type (ST) and wild type (WT) were examined during their life cycle in L929 and Vero cells. R. slovaca invaded the cytoplasm of the host cell by phagocytosis on the 1st d p.i. Rickettsiae adhering to the cytoplasmic membrane were engulfed by cellular extensions and occurred in phagocytic vacuoles. Binary fission of rickettsia was observed. The nuclear chromatin of eukaryotic cells was rearranged and condensed during 3rd and 6th d p.i. Finally, loss of the plasma membrane integrity, destruction of cytoplasm and nucleus resulted in cell lysis. Degeneration of the host cell caused by WT and ST was observed after 4 and 5 d p.i. in L929 cells and after 3 and 6 d p.i. in Vero cells, respectively. WT type was able to penetrate into the nucleus of the host cell and was responsible for dilatation of the perinuclear space and endoplasmic reticulum, causing more pronounced and different cytopathological changes than the ST.
- MeSH
- Cell Membrane microbiology ultrastructure MeSH
- Cell Nucleus microbiology ultrastructure MeSH
- Cell Line MeSH
- Chlorocebus aethiops MeSH
- Financing, Organized MeSH
- Culture Techniques MeSH
- Mice MeSH
- Rickettsia growth & development ultrastructure MeSH
- Rickettsia Infections microbiology MeSH
- Life Cycle Stages MeSH
- Vero Cells MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
Hollow-core particles, forming crystals in nuclei, prevailed in HeLa cells infected with an attenuated strain of pseudorabies virus (PRV). After infection with a virulent PRV strain, the cells contained mainly fully infectious dense-core particles. These findings might explain the lower susceptibility of HeLa and some other human cells to infection with attenuated strains of PRV as compared to virulent strains.
- MeSH
- Inclusion Bodies, Viral MeSH
- Cell Nucleus microbiology MeSH
- Cytopathogenic Effect, Viral MeSH
- Cytoplasm microbiology MeSH
- Microscopy, Electron MeSH
- HeLa Cells MeSH
- Herpesviridae growth & development MeSH
- Crystallography MeSH
- Herpesvirus 1, Suid pathogenicity growth & development ultrastructure MeSH
- Virus Replication MeSH
- Virulence MeSH
- MeSH
- Inclusion Bodies, Viral MeSH
- Cell Nucleus microbiology MeSH
- Cytopathogenic Effect, Viral MeSH
- Cytoplasm microbiology MeSH
- Microscopy, Electron MeSH
- HeLa Cells MeSH
- Herpesviridae growth & development MeSH
- Crystallography MeSH
- Herpesvirus 1, Suid pathogenicity growth & development ultrastructure MeSH
- Virus Replication MeSH
- Virulence MeSH
- MeSH
- Acridines MeSH
- Antigens MeSH
- Herpesvirus 1, Bovine immunology pathogenicity growth & development MeSH
- Inclusion Bodies, Viral MeSH
- Cell Nucleus microbiology MeSH
- Time Factors MeSH
- Cytoplasm microbiology MeSH
- Fluorescence MeSH
- Fluorescent Antibody Technique MeSH
- Culture Techniques MeSH
- Kidney MeSH
- Virus Replication MeSH
- Cattle MeSH
- Animals MeSH
- Check Tag
- Cattle MeSH
- Animals MeSH
