Protoplasma

http://link.springer.com/journal/709

List of Papers (Total 769)

Actin cytoskeleton in the extra-ovular embryo sac of Utricularia nelumbifolia (Lentibulariaceae)

The actin cytoskeleton in the mature female gametophyte of angiosperms has been examined in only a few dicot and monocot species. The main purposes of this study were to identify how the actin cytoskeleton is arranged in the mature extra-ovular embryo sac in Utricularia nelumbifolia (Lentibulariaceae). We found that the extra-ovular part of the central cell has a well-developed...

The novel functions of kinesin motor proteins in plants

Kinesin superfamily proteins are important microtubule-based motor proteins with a kinesin motor domain that is conserved among all eukaryotic organisms. They are responsible for unidirectionally transporting various cargos, including membranous organelles, protein complexes, and mRNAs. They also play critical roles in mitosis, morphogenesis, and signal transduction. Most...

Increased transcription in hydroxyurea-treated root meristem cells of Vicia faba

Hydroxyurea (HU), an inhibitor of ribonucleotide reductase, prevents cells from progressing through S phase by depletion of deoxyribonucleoside triphosphates. Concurrently, disruption of DNA replication leads to double-strand DNA breaks. In root meristems of Vicia faba, HU triggers cell cycle arrest (preferentially in G1/S phase) and changes an overall metabolism by global...

How do trypanosomes change gene expression in response to the environment?

All organisms are able to modulate gene expression in response to internal and external stimuli. Trypanosomes represent a group that diverged early during the radiation of eukaryotes and do not utilise regulated initiation of transcription by RNA polymerase II. Here, the mechanisms present in trypanosomes to alter gene expression in response to stress and change of host...

Is callose a barrier for lead ions entering Lemna minor L. root cells?

Plants have developed a range of strategies for resisting environmental stresses. One of the most common is the synthesis and deposition of callose, which functions as a barrier against stress factor penetration. The aim of our study was to examine whether callose forms an efficient barrier against Pb penetration in the roots of Lemna minor L. exposed to this metal. The obtained...

Gametophytic development of Brassica napus pollen in vitroenables examination of cytoskeleton and nuclear movements

Isolated microspores and pollen suspension of Brassica napus “Topas” cultured in NLN-13 medium at 18°C follow gametophytic pathway and develop into pollen grains closely resembling pollen formed in planta. This culture system complemented with whole-mount immunocytochemical technology and novel confocal laser scanning optical technique enables detailed studies of male gametophyte...

Space matters

As the other biological disciplines, cell biology has transcended its traditional borders and merged with other fields of biology. At first sight, this was accompanied by a certain loss of profile—what is cell biology actually doing these days? The answer to this question is much harder to formulate as compared to a few decades ago. In a period, where the unifying principles of...

Differences in protodermal cell wall structure in zygotic and somatic embryos of Daucus carota (L.) cultured on solid and in liquid media

The ultrastructure, cuticle, and distribution of pectic epitopes in outer periclinal walls of protodermal cells of Daucus carota zygotic and somatic embryos from solid and suspension culture were investigated. Lipid substances were present as a continuous layer in zygotic and somatic embryos cultured on solid medium. Somatic embryos from suspension cultures were devoid of cuticle...

Rays, intrusive growth, and storied cambium in the inflorescence stems of Arabidopsis thaliana (L.) Heynh

Arabidopsis thaliana is a model plant used in analysis of different aspects of plant growth and development. Under suitable conditions, secondary growth takes place in the hypocotyl of Arabidopsis plants, a finding which helps in understanding many aspects of xylogenesis. However, not all developmental processes of secondary tissue can be studied here, as no secondary rays and...

Effects of chloroplast dysfunction on mitochondria: white sectors in variegated leaves have higher mitochondrial DNA levels and lower dark respiration rates than green sectors

Co-ordination between plastids and mitochondria is so essential that there should be extensive inter-organellar crosstalk during development of plant cells. Indeed, chloroplast dysfunction in white leaves of plastid ribosome-deficient mutant barley, albostrians, is reportedly accompanied by increases in the levels of mitochondrial DNA and mitochondrial transcripts, suggesting...

Gating of aquaporins by heavy metals in Allium cepa L. epidermal cells

Changes in the water permeability, aquaporin (AQP) activity, of leaf cells were investigated in response to different heavy metals (Zn2+, Pb2+, Cd2+, Hg2+). The cell pressure probe experiments were performed on onion epidermal cells as a model system. Heavy metal solutions at different concentrations (0.05 μM–2 mM) were used in our experiments. We showed that the investigated...

Embryogenesis in Sedum acre L.: structural and immunocytochemical aspects of suspensor development

The changes in the formation of both the actin and the microtubular cytoskeleton during the differentiation of the embryo-suspensor in Sedum acre were studied in comparison with the development of the embryo-proper. The presence and distribution of the cytoskeletal elements were examined ultrastructurally and with the light microscope using immunolabelling and rhodamine...

Plant cell harakiri—programmed cell death in development

The organisation of a multicellular organism requires that individual cells subjugate their needs for resources and their propagation under control of supercellular signals. The ultimate form of this cellular altruism is programmed cell death, a response that fulfils several basic functions in plants and other multicellular organisms: it participates in tissue differentiation and...

New data about the suspensor of succulent angiosperms: Ultrastructure and cytochemical study of the embryo-suspensor of Sempervivum arachnoideum L. and Jovibarba sobolifera (Sims) Opiz

The development of the suspensor in two species — Sempervivum arachnoideum and Jovibarba sobolifera — was investigated using cytochemical methods, light and electron microscopy. Cytological processes of differentiation in the embryo-suspensor were compared with the development of embryo-proper. The mature differentiated suspensor consists of a large basal cell and three to four...

Female germ unit in Genlisea and Utricularia, with remarks about the evolution of the extra-ovular female gametophyte in members of Lentibulariaceae

Lentibulariaceae is the largest family among carnivorous plants which displays not only an unusual morphology and anatomy but also the special evolution of its embryological characteristics. It has previously been reported by authors that Utricularia species lack a filiform apparatus in the synergids. The main purposes of this study were to determine whether a filiform apparatus...

The dynamics of the actin cytoskeleton during sporogenesis in Psilotum nudum L.

The actin cytoskeleton (microfilaments, MFs) accompanies the tubulin cytoskeleton (microtubules) during the meiotic division of the cell, but knowledge about the scope of their physiological competence and cooperation is insufficient. To cast more light on this issue, we analysed the F-actin distribution during the meiotic division of the Psilotum nudum sporocytes. Unfixed...

Cell cycle-dependent phosphorylation of pRb-like protein in root meristem cells of Vicia faba

The retinoblastoma tumor suppressor protein (pRb) regulates cell cycle progression by controlling the G1-to-S phase transition. As evidenced in mammals, pRb has three functionally distinct binding domains and interacts with a number of proteins including the E2F family of transcription factors, proteins with a conserved LxCxE motif (D-type cyclin), and c-Abl tyrosine kinase. CDK...