Origin of the brushborder in the differentiating midgut of Melasoma saliceti (Chrysomelidae, Coleoptera) embryos

The embryonic development of Melasoma saliceti takes eight days at room temperature. At the beginning of the 5th day the endoderm cells have already formed a unilayered epithelium of the midgut primordium. The midgut epithelium is formed by flat cells that are not connected by specialized intercellular junctions. Large vesicles can be seen in dilated intercellular spaces of the epithelium. Cytoplasmic projections, similar to microvilli, appear in the vesicles. During the 5th day of development, the vesicles grow and become enclosed by the intercellular junctions of a zonula adherens type. During the 6th day of development the cell junctions surrounding the vesicles become transformed into a septate type.On the 8th day of development the vesicles come close to the apical sides of the midgut cells and open towards the yolk. At the same time the microvilli spread over the apical surface of the midgut primordium to form the regular brushborder of the larval midgut. In the species studied the vesicles appear to preabricate the apical surfaces of the future midgut epithelium

Analysis of the behavior of mitochondria in the ovaries of the earthworm Dendrobaena veneta Rosa 1839

We examined six types of cells that form the ovary of the earthworm Dendrobena veneta ogonia, prooocytes, vitellogenic oocytes, trophocytes, fully grown postvitellogenic oocytes and somatic cells of the gonad. The quantitative stereological method revealed a much higher "volume density" of mitochondria in all of the types of germ-line cells except for the somatic cells. Fluorescent vital stain JC-1, however, showed a much higher oxidative activity of mitochondria in the somatic cells than in the germ-line cells. The distribution of active and inactive mitochondria within the studied cells was assessed using the computer program ImageJ. The analysis showed a higher luminosity of inactive mitochondria in all of the types of germ-line cells and a higher luminosity of active mitochondria in somatic cells. The OXPHOS activity was found in somatic cells mitochondria and in the peripheral mitochondria of the vitellogenic oocytes. The detection of reactive oxygen species (ROS) revealed a differentiated distribution of ROS in the different cell types. The amount of ROS substances was lower in somatic cells than in younger germ-line cells. The ROS level was also low in the cytoplasm of fully grown postwitellogenic oocytes. The distribution of the MnSOD enzyme that protects mitochondria against destructive role of ROS substances was high in the oogonia and in prooocytes and it was very high in vitellogenic and postvitellogenic oocytes. However, a much lower level of this protective enzyme was observed in the trophocytes and the lowest level was found in the cytoplasm of somatic cells. The lower mitochondrial activity and higher level of MnSOD activity in germ-line cells when compared to somatic cells testifies to the necessity of the organisms to protect the mitochondria of oocytes against the destructive role of the ROS that are produced during oxidative phosphorylation. The protection of the mitochondria in oocytes is essential for the transfer of healthy organelles to the next generation.Department of Animal Histology and Embryology, University of Silesia, Katowice, Polan

Differentiation of regenerative cells in the midgut epithelium of epilachna cf. nylanderi (Mulsant 1850) (insecta, coleoptera, coccinellidae)

Differentiation of regenerative cells in the midgut epithelium of Epilachna cf. nylanderi (Mulsant 1850) (Insecta, Coleoptera, Coccinellidae), a consumer of the Ni-hyperaccumulator Berkheya coddii (Asteracae) from South Africa, has been monitored and described. Adult specimens in various developmental phaseswere studiedwith the use of lightmicroscopy and transmission electron microscopy. All degenerated epithelial cells are replaced by newly differentiated cells. They originate from regenerative cells which act as stem cells in the midgut epithelium. Just after pupal-adult transformation, the midgut epithelium of E. nylanderi is composed of columnar epithelial cells and isolated regenerative cells distributed among them. The regenerative cells proliferate intensively and form regenerative cell groups. In each regenerative cell group the majority of cells differentiate into new epithelial cells, while some of them still act as stem cells and persist as a reservoir of cells capable for proliferation and differentiation. Because this species is an obligate monophage of plants which accumulate nickel, proliferation and differentiation

Continuity in language: styles and registers in literary and non-literary discourse

Praca recenzowana / peer-reviewed paperIntroduction: "Linguistic diversity captured with the terms style and register is of interest to literary theory and to linguistic theory, as both are concerned with how individuals and the multiple social groups and networks that they can simultaneously be members of articulate themselves and how they distinguish themselves from others, the reasons that speakers/writers may have for their choice of linguistic forms, the ways in which these linguistic forms can be creatively exploited in particular contexts as well as with the effects that the choices and departures from norms or conventions of use may have on the hearers/readers. Among the issues of common interest to literary and linguistic theory are the formal, cultural, historical, axiological, moral, ideological, social, psychological, hermeneutic, and other aspects of the structure, production and perception of language. These aspects are traditionally studied in relation to general concepts of convention and creativity, literalness and fictionality, objectivity and subjectivity, politeness and power, consensus and conflict, class and stigma, affect, personal identity and allegiance, and many others."(...

Merged images of <i>Dendrobaena veneta</i> ovary treated with JC-1 cationic stain showing all cell types buiding the gonad.

<p>The green fluorescence shows inactive and the red one active mitochondria in the cells. <i>A</i>. Zones I and II (and part of the zone III with previtellogenic oocytes (O) of a JC-1 stained gonad. A green fluorescence can be seen in the cytoplasm of both the oogonia (asterisks) and the prooocytes (P). A red one prevails in the somatic cells (arrowheads). Confocal microscope, JC-1 staining, magn. x600. <i>B</i>. Zone III. Previtellogenic oocytes (O) and trophocytes (T) immersed in a network of follicular cells (S). The germ-line cells express green fluorescence which testifies to the decreased activity of their mitochondria. In some trophocytes individual red marks are visible (arrows). The somatic cells (arrowheads) express the strong red fluorescence of highly active mitochondria. Confocal microscope, JC-1 staining, magn. x800. <i>C</i>. The oldest vitellogenic oocyte from zone IV surrounded by a few layers of somatic cells (S). The green fluorescence of inactive mitochondria dominates in the oocyte (O) while the red fluorescence of active mitochondria is mainly visible in the somatic cells. Confocal microscope, JC-1 staining, magn. x720.</p

Detection of ROS in all the ovary constituents.

<p><i>A</i>. Zone II of the ovary. In some prooocytes the signal is emitted by the entire nucleus (arrowheads). In the other the signal is limited to a smaller nucleus region (arrows) and is also visible in the cytoplasm (asterisks). Confocal microscope, DHE staining, magn. x750. <i>B</i>. Zone III of the ovary. ROS detection. Nuclei (n) of the growing oocytes (o) emit the weakest signal among the ovary cells with a strong signal from the cytoplasm. Between oocytes there are somatic cells (S) with the smallest amount of reactive oxygen species. Among trophocytes (T) there are cells with a low amount of ROS but the degenerating trophocytes express a much stronger signal (asterisk). Confocal microscope, DHE staining, magn. x 760. <i>C</i>. ROS in a vitellogenic oocyte (O) and surrounding somatic cells (s). Characteristic crescent-shaped fragment of the nucleus (arrowhead). Another section plane shows the circular profile of the structure (inset). The signal from the cytoplasm is weaker than in younger oocytes. Somatic cells surrounding the oocyte emit a strong signal from the nuclei (arrows). Confocal microscope, DHE staining, magn. x1500. <i>D</i>. Somatic cells of the gonad emit a strong signal from the nuclei (arrows) and a much weaker one from the cytoplasm. Confocal microscope, DHE staining, magn. x2000.</p

Three sets of image segmentation of the JC-1 stained ovary fragments performed using the Multi Otsu Threshold plug-in for the ImageJ computer program.

<p>Zone I and zone II (z1, z2). Two rows of pictures showing the image segmentation of the JC-1 stained ovary fragments. The upper row shows the four classes of red fluorescence intensity (A1 to A4); the lower row shows the four classes of green fluorescence intensity (N1–N4). In oogonia (asterisks) A1 to A3 activity is seen, A4 is present in some of the gonial cells. In prooocytes (P) mainly A1 and A2 activity is visible. A3 is seen only in some cells and A4 is almost absent. In oogonia (asterisks) inactive mitochondria are seen in all four classes of fluorescence intensity (N1 to N4) although the latter is distributed irregularly. In prooocytes (P) inactive mitochondria are distributed in entire cytoplasm (N1 to N3) but inactive mitochondria of N4 class are distributed so irregularly that they are seen only in some cells (arrows) on the presented section. In somatic cells both A1 and N1 fluorescence are low but A2 to A4 and N2 to N4 are expressed with a similar intensity. Confocal microscope, JC-1 staining, magn. x500. Zone III (z3). Two rows of pictures showing the image segmentation of the JC-1 stained ovary fragments. The upper row shows the four classes of red fluorescence intensity (A1 to A4); the lower row shows the four classes of green fluorescence intensity (N1–N4). In the oocytes (O) fluorescence intensity of A1 and A2 classes are seen. Activity of A3 class is weaker and A4 is absent. In the lower row the fluorescence intensity of inactive mitochondria of N1 to N3 classes is strong and N4 class is also noticed. In the trophocytes (T) the fluorescence intensity of A1 to A3 classes is visible and in the class A4 single signals are noticed. In the green fluorescence the fluorescence of all N1 to N4 classes occur. In somatic cells both A1 and N1 fluorescence are clearly visible and A2 to A4 and N2 to N4 are expressed with similar intensity. Confocal microscope, JC-1 staining, magn. x600. Zone IV (z4). Two rows of pictures showing the image segmentation of the JC-1 stained ovary fragments. The upper row shows the four classes of red fluorescence intensity (A1 to A4), the lower row shows the four classes of green fluorescence intensity (N1–N4). In the vitellogenic oocyte (O) fluorescence intensity of A1is visible almost regularly in ooplasm and A2 occurs in the subplasmalemmal position. Activity of A3 class is restricted to one of the cell poles and A4 gives individual signals (arrows). In the lower row the intensity of inactive mitochondria of class N1 is restricted to the internal cytoplasm, the class N2 is situated in the outer part of the ooplasm and N3 is shifted to one of the poles but N4 is absent. In somatic cells (s) both A1 and N1 fluorescence are low, A2 and N2 are very similar but A3 and N3 are almost identical. While A4 is apparent (arrowheads) N4 is almost absent. Confocal microscope, JC-1 staining, magn. x400.</p

Numerical data of stereological results.

<p>Numerical data of the stereological results showing parts of the cell volume that is occupied by: mito – mitochondria, aG – Golgi bodies, nu – nucleus and cyto – cytoplasm in particular cells of the <i>D</i>. <i>veneta</i> gonad. SOM – somatic cells, OOG – oogonia, PRO – prooocytes, TRO – trophocytes, VO – vitellogenic oocytes.</p><p>Numerical data of stereological results.</p

Morphology of <i>Dendrobaena veneta</i> ovary showing the ultrastructure of all cell types building the earthworm’s gonad.

<p><i>A</i>. Longitudinal section of the ovary with the attachment site to the intersegmental wall (asterisk). Roman numbers indicate the 4 zones of the gonad: zone I – close to the attachment site contains oogonia; zone II – where differentiation of the prooocytes occurs; zone III – previtellogenesis and vitellogenesis with the growing oocytes (O) and the trophocytes (T); zone IV – where postvitellogenic oocytes (PO) detach from the ovary to swim freely in the coelomic fluid. Degenerating trophocytes (arrows) are embedded in the somatic cells (arrowheads) surrounding the oocytes. All germ-line cells are immersed within the framework made by the somatic cells. Light microscopy, semithin section, magn. x240. <i>B</i>. Oogonia (og) with almost spherical nuclei with characteristic clumps of chromatin are tightly enveloped by somatic cells (arrowheads). TEM, magn. x6700. <i>C</i>. In the cytoplasm of the young oocyte (O) with nucleus (n), numerous Golgi bodies (G) and mitochondria (m) are visible. The oocyte is connected to other members of the cluster (trophocytes) by a cytoplasmic cord (asterisk). The oocyte is surrounded by somatic cells that are firmly connected by extensive desmosomes (arrow). TEM, magn. x6600. <i>D</i>. The somatic cell of the gonad. Beside nucleus (n), Golgi bodies (G) and a few mitochondria (m), there is a huge number of intermediate filaments (f) in its’ cytoplasm. TEM, magn. x18800. <i>E</i>. Among the growing oocytes (O) of zone III of the ovary, there are numerous trophocytes (T) and some somatic cells (arrows). Light microscope, semithin section, magn. x1300. <i>F</i>. Pro-oocyte with synaptonemal complexes in the nucleus (arrow), mitochondria (m) and Golgi bodies (G) in the cytoplasm can be seen. TEM, magn. x20000. <i>G</i>. Postvitellogenic oocyte (O) of zone IV of the ovary surrounded by some layers of the somatic cells (arrowheads). A group of degenerating nurse cells is visible close to the oocyte (arrow). Light microscope, semithin section, magn. x1200.</p