Comparison of microfilament patterns in nurse cells of different insects with polytrophic and telotrophic ovarioles

Development ◽  
1986 ◽  
Vol 93 (1) ◽  
pp. 291-301
Author(s):  
Herwig O. Gutzeit ◽  
Erwin Huebner
Keyword(s):  
Leptinotarsa Decemlineata ◽  
Nurse Cell ◽  
Cell Membranes ◽  
Central Area ◽  
Nurse Cells ◽  
Oryzaephilus Surinamensis ◽  
Actin Network ◽  
Cell Cytoplasm ◽  
Microfilament Bundles ◽  
Apis Mellifica

The localization of F-actin (microfilaments) in the nurse cells of ovarian follicles has been studied in 12 different insect species by fluorescence microscopy after specifically staining F-actin with rhodamine-conjugated phalloidin. In the analysed species with polytrophic ovaries (Apis mellifica, Pimpla turionellae, Bradysia tritici, Ephestia kuehniella, Protophormia terraenovae) a dense F-actin network was found to be associated with the nurse cell membranes. Only in Protophormia were microfilament bundles seen to extend from the cell membrane into the nurse cell cytoplasm and in a few cases appeared to make contact with the nuclear membrane. In the analysed coleopteran species with telotrophic ovarioles (Strangalia melanura, Leptinotarsa decemlineata, Oryzaephilus surinamensis) the fluorescence was also concentrated at the nurse cell membranes only. However, in all analysed hemipteran species (Lygus pratensis, Calocoris affinis, Graphosoma lineatum, Euscelis plebejus) the microfilament pattern was very different: while the nurse cells stained only weakly, we always found a characteristic (in some species massive) microfilament network surrounding the trophic core, a central area in the germarium from where material is transported through the trophic cords into the oocytes. The observed differences in the microfilament patterns are likely to reflect different mechanisms for transporting macromolecules and organelles within the ovariole.

Evidence against electrophoresis as the principal mode of protein transport in vitellogenic ovarian follicles of Drosophila

Development ◽  
1987 ◽  
Vol 101 (2) ◽  
pp. 279-288
Author(s):  
J. Bohrmann ◽  
H. Gutzeit
Keyword(s):  
Nurse Cell ◽  
Protein Transport ◽  
Exchange Chromatography ◽  
Heterologous Proteins ◽  
Nurse Cells ◽  
Cell Cytoplasm ◽  
Two Dimensional Gel Electrophoresis ◽  
Electrophoretic Transport ◽  
Indicator Dyes

Charged cell constituents in polytrophic insect follicles are thought to be transported in the nurse cell-oocyte syncytium by way of electrophoresis. This concept, proposed by Woodruff & Telfer (1980) was based on electrophysiological data and microinjection of heterologous proteins using Hyalophora follicles. By microinjecting fluorescently labelled acidic and basic proteins into the nurse cells or oocyte of vitellogenic Drosophila follicles, we failed to obtain evidence for charge-dependent migration of these molecules. We have also analyzed the proteins of nurse cells and oocyte on isoelectric focusing gels, by means of two-dimensional gel electrophoresis, and by ion exchange chromatography to see if basic or acidic proteins accumulate in vivo in nurse cells and oocyte, respectively. For the bulk of the follicular proteins we found no accumulation. Further evidence against an electrophoretic transport system in Drosophila was obtained by estimating the intracellular pH from the colour of indicator dyes microinjected into the follicles; the results indicate that the pH in the nurse cell cytoplasm is lower than that in the ooplasm. According to the model developed for Hyalophora, electrophoretic transport would be favoured by high pH in the nurse cell cytoplasm.

Time-lapse film analysis of cytoplasmic streaming during late oogenesis of Drosophila

Development ◽  
1982 ◽  
Vol 67 (1) ◽  
pp. 101-111
Author(s):  
Herwigo Gutzeit ◽  
Roswitha Koppa
Keyword(s):  
Cytoplasmic Streaming ◽  
Nurse Cell ◽  
Time Lapse ◽  
Nurse Cells ◽  
Film Analysis ◽  
Cell Cytoplasm ◽  
Morphological Criteria ◽  
Oocyte Stage

Cytoplasmic streaming in follicles of Drosophila has been analysed in vitro by means of time-lapse films. Late vitellogenic follicles develop normally in vitro as judged by morphological criteria. Furthermore, follicles (stage 10 and younger) which were cultured in vitro for the same length of time as follicles which were filmed, developed normally in vivo after injection into a host fly. The recorded cytoplasmic movements are, therefore, unlikely to be an in vitro artefact. At early vitellogenic stages (up to stage 9; King, 1970) no cytoplasmic streaming can be detected, but at stage 10A cytoplasmic movements are initiated within the oocyte. At stage 10B, when the nurse cells start degenerating, nurse cell cytoplasm can be seen to flow into the growing oocyte. At stage 11 a central stream of nurse-cell cytoplasm reaches the oocyte within a minute. The ooplasmic streaming is most rapid at stage 10B and stage 11 and only an oocyte cortex up to 7 μm thick remains stationary. Once the bulk of the nurse-cell cytoplasm has poured into the oocyte (stage 12) the cytoplasmic movement ceases, first in the nurse cells and later in the ooplasm. In mature oocytes no cytoplasmic streaming can be detected.

Differences and similarities of nurse cells in cysts of Trichinella spiralis and T. pseudospiralis

2004 ◽  
Vol 78 (1) ◽  
pp. 7-16 ◽  
Author(s):  
T. Boonmars ◽  
Z. Wu ◽  
I. Nagano ◽  
T. Nakada ◽  
Y. Takahashi
Keyword(s):  
Alkaline Phosphatase ◽  
Satellite Cells ◽  
Nurse Cell ◽  
Trichinella Spiralis ◽  
Intermediate Filament Protein ◽  
Nurse Cells ◽  
Cell Cytoplasm ◽  
Trichinella Pseudospiralis ◽  
Eosinophilic Cytoplasm ◽  
Filament Protein

AbstractThe nurse cell in the cyst of Trichinella spiralis comprises at least two kinds of cytoplasm, derived from muscle or satellite cells, as indicated by the pattern of staining using regular dye (haematoxylin and eosin, or toluidine blue), alkaline phosphatase (ALP) expression, acid phosphatase (ACP) expression and immunostaining with an anti-intermediate filament protein (desmin or keratin). Muscle cells undergo basophilic changes following a T. spiralis infection and transform to the nurse cells, accompanied by an increase in ACP activity and the disappearance of desmin. Satellite cells are activated, transformed and joined to the nurse cells but remain eosinophilic. The eosinophilic cytoplasm is accompanied by an increase in desmin and ALP expression but not an increase in ACP activity. Differences in the staining results for ALP or ACP suggest that the two kinds of cytoplasm have different functions. Trichinella pseudospiralis infection results in an increase of ACP activity at a later stage than T. spiralis. There is also a difference in the location pattern of ACP in the cyst of T. spiralis compared with T. pseudospiralis. In T. spiralis, ACP is diffused within the cell, but in T. pseudospiralis, ACP distribution is spotty corresponding to the location of the nucleus. Trichinella pseudospiralis infection is accompanied by a slight increase in ALP activity. Activated satellite cells following a T. pseudospiralis infection exhibit an increase in desmin expression. The present study therefore reveals that nurse cell cytoplasm differs between the two Trichinella species and between the two origins of cytoplasm in the cyst of T. spiralis.

The role of microfilaments in cytoplasmic streaming in Drosophila follicles

1986 ◽  
Vol 80 (1) ◽  
pp. 159-169 ◽  
Author(s):  
H.O. Gutzeit
Keyword(s):  
Cell Membrane ◽  
Nuclear Membrane ◽  
Actin Filaments ◽  
Cytoplasmic Streaming ◽  
Nurse Cell ◽  
Time Lapse ◽  
Nurse Cells ◽  
Cell Nuclei ◽  
Cell Cytoplasm

During the last phase of oogenesis in Drosophila, nurse cell cytoplasm can be seen to be streaming into the growing oocyte when visualized in time-lapse films. This process can be reversibly inhibited by cytochalasins. The distribution of F-actin filaments in the nurse cells has been studied by staining with rhodamine-conjugated phalloidin. At the beginning of cytoplasmic streaming (stage 10B) increasingly thick bundles of microfilaments formed, many of which spanned the nurse cell cytoplasm from the cell membrane to the nuclear membrane. The association of F-actin with the nuclear membrane persisted when nurse cell nuclei were isolated mechanically. The experimental evidence suggests that microfilament contraction in the nurse cells leads to cytoplasmic streaming by pressure flow.

Localisation of potassium pumps in Drosophila ovarian follicles

Zygote ◽  
1994 ◽  
Vol 2 (3) ◽  
pp. 189-200 ◽  
Author(s):  
Johannes Bohrmann ◽  
Ulf-Rüdiger Heinrich
Keyword(s):  
Nurse Cell ◽  
Cell Membranes ◽  
Plasma Membranes ◽  
Ionic Current ◽  
Ovarian Follicles ◽  
Follicle Cells ◽  
Potassium Ions ◽  
Nurse Cells ◽  
Strong Activity ◽  
Development Processes

SummaryIt has been shown previously that, in Drosophila oogenesis, potassium ions are important for bioelectric phenomena as well as for other physiological and development processes. In the present study we determined the spatial distribution and activity of the (Na+, K+)-pump and of ouabain-insensitive K+ pumps in plasma membranes of vitellogenic ovarian follicles (stage 10). We used that light micorscopic anthroylouabain method as well as the cytochemical lead and cerium precipitation methods in combination with electron spectroscopic imaging (ESI) and elelctronm energy-loss spectroscopy (EELS). (Na+, K+)-ATPase activity was predominantly observed on the oolemma as well as on the membranes of the columnar follicle cells covering the oocyte, whereas on the membranes of the nurse cells and of the squamous follicle cells covering the nurse cells the activity was vary low. The highset activity of the (Na+ K+)-pump was found at the anterior and posterior ends of the oocute, and this on the oolemma as well as on the membranes of the follicle cells located here. Strong activity of ouabain-insensitive K+-pumps was observed on most of the oolemma (except at the anterior of the oocyte) and on the membranes of some nurse cells located next to the oocyte, whereas less activity was found on the other nurse cell membranes and on the membranes of all follicle cells. The suitability of the differnet methods nurse cell membranes and on the membrances of all follicle cells. The suitability of th different methods used for determining the localisation as well as the activity of K+-pumps is discussed. We further discuss the nature of the ouabain-insensitive K+ pumps and the relevance of the observed distribution of K+-pumps for K+ uptake, extrafollicular ionic current flow intercelluar signalling and other developmental processes in Drosophila oogenesis.

scholarly journals Nurse cell-derived small RNAs define paternal epigenetic inheritance in Arabidopsis

2021 ◽  
Author(s):  
Jincheng Long ◽  
James Walker ◽  
Wenjing She ◽  
Billy Aldridge ◽  
Hongbo Gao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Small Rnas ◽  
Nurse Cell ◽  
De Novo ◽  
Epigenetic Inheritance ◽  
Genome Integrity ◽  
Nurse Cells ◽  
Male Germline ◽  
Methylation Patterns

AbstractThe plant male germline undergoes DNA methylation reprogramming, which methylates genes de novo and thereby alters gene expression and facilitates meiosis. Why reprogramming is limited to the germline and how specific genes are chosen is unknown. Here, we demonstrate that genic methylation in the male germline, from meiocytes to sperm, is established by germline-specific siRNAs transcribed from transposons with imperfect sequence homology. These siRNAs are synthesized by meiocyte nurse cells (tapetum) via activity of the tapetum-specific chromatin remodeler CLASSY3. Remarkably, tapetal siRNAs govern germline methylation throughout the genome, including the inherited methylation patterns in sperm. Finally, we demonstrate that these nurse cell-derived siRNAs (niRNAs) silence germline transposons, thereby safeguarding genome integrity. Our results reveal that tapetal niRNAs are sufficient to reconstitute germline methylation patterns and drive extensive, functional methylation reprogramming analogous to piRNA-mediated reprogramming in animal germlines.

The endocycle controls nurse cell polytene chromosome structure during Drosophila oogenesis

Development ◽  
1999 ◽  
Vol 126 (2) ◽  
pp. 293-303 ◽  
Author(s):  
K.J. Dej ◽  
A.C. Spradling
Keyword(s):  
Polytene Chromosome ◽  
Nurse Cell ◽  
Chromosome Structure ◽  
Polytene Chromosomes ◽  
S Phase ◽  
Nurse Cells ◽  
Chromosome Behavior ◽  
M Phase ◽  
Diploid Cells ◽  
Polytene Nuclei

Polytene chromosomes exhibit intricate higher order chromatin structure that is easily visualized due to their precisely aligned component strands. However, it remains unclear if the same factors determine chromatin organization in polyploid and diploid cells. We have analyzed one such factor, the cell cycle, by studying changes in Drosophila nurse cell chromosomes throughout the 10 to 12 endocycles of oogenesis. We find that nurse cells undergo three distinct types of endocycle whose parameters are correlated with chromosome behavior. The first four endocycles support complete DNA replication; poorly banded polytene euchromatin progressively condenses during the late S phases to produce blob-like chromosomes. During the unique fifth endocycle, an incomplete late S phase is followed by a mitosis-like state during which the 64C chromosomes dissociate into 32 chromatid pairs held together by unreplicated regions. All the subsequent endocycles lack any late S phase; during these cycles a new polytene chromosome grows from each 2C chromatid pair to generate 32-ploid polytene nuclei. These observations suggest that euchromatin begins to condense during late S phase and that nurse cell polytene chromosome structure is controlled by regulating whether events characteristic of late S and M phase are incorporated or skipped within a given endocycle.

maelstrom is required for an early step in the establishment of Drosophila oocyte polarity: posterior localization of grk mRNA

Development ◽  
1997 ◽  
Vol 124 (22) ◽  
pp. 4661-4671 ◽  
Author(s):  
N.J. Clegg ◽  
D.M. Frost ◽  
M.K. Larkin ◽  
L. Subrahmanyan ◽  
Z. Bryant ◽  
...  
Keyword(s):  
Nurse Cell ◽  
Egf Receptor ◽  
Mrna Localization ◽  
Follicle Cells ◽  
Rna Transport ◽  
Nurse Cells ◽  
Loss Of Function ◽  
Cell Fates ◽  
Early Step ◽  
Novel Protein

We describe a mutant, maelstrom, that disrupts a previously unobserved step in mRNA localization within the early oocyte, distinct from nurse-cell-to-oocyte RNA transport. Mutations in maelstrom disturb the localization of mRNAs for Gurken (a ligand for the Drosophila Egf receptor), Oskar and Bicoid at the posterior of the developing (stage 3–6) oocyte. maelstrom mutants display phenotypes detected in gurken loss-of-function mutants: posterior follicle cells with anterior cell fates, bicoid mRNA localization at both poles of the stage 8 oocyte and ventralization of the eggshell. These data are consistent with the suggestion that early posterior localization of gurken mRNA is essential for activation of the Egf receptor pathway in posterior follicle cells. Posterior localization of mRNA in stage 3–6 oocytes could therefore be one of the earliest known steps in the establishment of oocyte polarity. The maelstrom gene encodes a novel protein that has a punctate distribution in the cytoplasm of the nurse cells and the oocyte until the protein disappears in stage 7 of oogenesis.

scholarly journals POLARIZED INTERCELLULAR BRIDGES IN OVARIAN FOLLICLES OF THE CECROPIA MOTH

1973 ◽  
Vol 58 (1) ◽  
pp. 172-188 ◽  
Author(s):  
Richard I. Woodruff ◽  
William H. Telfer
Keyword(s):  
Nurse Cell ◽  
Electrical Potential ◽  
The Other ◽  
Rabbit Serum ◽  
Nurse Cells ◽  
Recording Electrode ◽  
Serum Globulin ◽  
Intercellular Bridges ◽  
Apical Cytoplasm ◽  
Unidirectional Movement

Fluorescein-labeled rabbit serum globulin was injected into vitellogenic oocytes of the cecropia moth. Though the label spread throughout the ooplasm in less than 30 min, it was unable even after 2 h to cross the complex of intercellular bridges connecting the oocyte to its seven nurse cells. After injection into a single nurse cell, fluorescence was detected in the oocyte adjacent to the bridge complex within 3 min and had spread throughout the ooplasm in 30 min. Here also, the cell bodies of the six uninjected nurse cells remained nonfluorescent. Four of the nurse cells are not bridged directly to the oocyte but only through the apical ends of their siblings. Unidirectional movement must therefore occur in the apical cytoplasm of the nurse cells, as well as in the intercellular bridges. The nurse cells of healthy follicles had an intracellular electrical potential -40 mV relative to blood or dissecting solution, while oocytes measured -30 mV. A mV difference was also detected by direct comparison between a ground electrode in one cell and a recording electrode in the other. Three conditions were found in which the 10 mV difference was reduced or reversed in polarity. In all three cases fluorescent globulin was able in some degree to cross the bridges from the oocyte to the nurse cells.

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