scholarly journals Gonads and gametogenesis in Chaetodactylus osmiae (Acariformes: Astigmata: Chaetodactylidae) a parasite of solitary bees

Acarologia ◽  
2018 ◽  
Vol 58 (4) ◽  
pp. 801-824
Author(s):  
Elżbieta Rożej-Pabijan ◽  
Wojciech Witaliński
Keyword(s):  
Germ Line ◽  
Heterogeneous Material ◽  
Ultrastructural Level ◽  
The Body ◽  
Reproductive Systems ◽  
Ovarian Cell ◽  
Nutritive Cell ◽  
Spongy Layer ◽  
Vitelline Envelope ◽  
Germinal Cells

Chaetodactylus osmiae (Dufour, 1839) is a mite parasitizing the solitary bee - Osmia rufa L.- used as a commercial pollinator. In this study we present the anatomy of female and male reproductive systems of this species as well as its gonadal structure and gametogenesis at the ultrastructural level. The reproductive systems are similar to those of other Astigmata. The ovaries are paired and each contains germ-line cells – a giant nutritive ovarian cell connected via funnel-type intercellular bridges to oogonia and previtellogenic oocytes. Germinal cells are embedded in several large somatic stroma cells. Remarkable numerous protrusions of the nutritive ovarian cell penetrate into the stroma cell cytoplasm. Conspicuous ER cisterns run close and parallel to the surface of the germinal cells. Oocytes entering vitellogenesis disassociate with the nutritive cell and a vitelline envelope composed of heterogeneous material appears on their surface. When vitellogenesis is completed, the oocytes are full of lipid droplets and two types of yolk spheres; the vitelline envelope transforms into a thin and homogeneous chorion.Paired testes are located on one side of the body, whereas the opposite side is filled by a male accessory gland. In testis, germinal cells are embedded in a few somatic stroma cells. The earliest spermatogonia form a compact germarium, whereas later stages are dispersed randomly within the testis. Spermatocytes are characterized by a superficial spongy layer, formation of mitochondrial derivatives, loss of nuclear envelope and condensation of chromatin in threads. A single electron-dense lamella appears during the spermatid stage, separating chromatin threads from a large spongy body surrounded by arcuate, double-membrane bounded cisterns. In spermatids, the superficial spongy layer is absent. The testicular central cell in the germarium and structures related to meiotic division were not observed in the testes. Spermatozoa are multiform cells (approx. 4x11µm) containing electron-dense lamella (ca. 45 nm thick) surrounded by mitochondrial derivatives which separate chromatin threads 45-50 nm thick from remnants of the spongy body i.e. arcuate cistern profiles. Spermatozoa deposited in female spermatheca are more electron dense; the electron-dense lamella is deeply folded several times, whereas chromatin threads are present in the center of the spermatozoon and are either flanked by lamella folds or located more peripherally under the plasmalemma. Remnants of the spongy body are not discernible.

Probing Drosophila gene function by antisense RNA

Genome ◽  
1989 ◽  
Vol 31 (1) ◽  
pp. 422-425 ◽  
Author(s):  
Reinhard Schuh ◽  
Herbert Jäckle
Keyword(s):  
Antisense Rna ◽  
Germ Line ◽  
Conventional Technique ◽  
Transcription Unit ◽  
The Body ◽  
Mutant Phenotype ◽  
Drosophila Embryo ◽  
Alternative Approach ◽  
Pattern Forming ◽  
Germ Line Transformation

The conventional technique for assigning a particular genetic function to a cloned transcription unit has relied on the rescue of the mutant phenotype by germ line transformation. An alternative approach is to mimic a mutant phenotype by the use of antisense RNA injections to produce phenocopies. This approach has been successfully used to identify genes involved in early pattern forming processes in the Drosophila embryo. At the time when antisense RNA is injected, the embryo develops as a syncytium composed of about 5000 nuclei which share a common cytoplasm. The gene interactions required to establish the body plan occur before cellularization at the blastoderm stage. Thus the nuclei and their exported transcripts are accessible to the injected antisense RNA. The antisense RNA interferes with the endogenous RNA by an as yet unidentified mechanism. The extent of interference is only partial and produces phenocopies with characteristics of weak mutant alleles. In our lab and others, this approach has been successfully used to identify several genes required for normal Drosophila pattern formation.Key words: Drosophila segmentation, phenocopy, antisense RNA, Krüppel gene.

XY follicle cells in ovaries of XX—XY female mouse chimaeras

Development ◽  
1988 ◽  
Vol 104 (4) ◽  
pp. 683-688 ◽  
Author(s):  
P.S. Burgoyne ◽  
M. Buehr ◽  
A. McLaren
Keyword(s):  
Female Mouse ◽  
Germ Line ◽  
Follicle Cells ◽  
Cell Type ◽  
Ovarian Cell ◽  
Female Mice ◽  
Xy Female

Oocytes with adhering follicle cells were sampled from ovaries obtained from 11 GPI-1A—GPI-1B chimaeras, comprising 10 females and 1 hermaphrodite. GPI analysis of individual oocytes revealed a marked bias towards the GPI-1B component in the germ line of this chimaeric combination. GPI-1B XY oocytes were identified in the ovary from the hermaphrodite, the bias towards the GPI-1B germ line perhaps helping to counterbalance the normally severe selection against XY oocytes. GPI analysis of follicle cells revealed a much more balanced contribution of the two components to this ovarian cell type. Importantly, GPI-1A follicle cells were identified in more than half the follicles from an XX—XY female in which the GPI-1A component was XY, supporting an earlier conclusion of Ford et al. (1974) that XY cells can contribute to the follicles of XX—XY female mice. It is suggested that XY cells can be recruited to form follicle cells in XX—XY chimaeras when there is a developmental mismatch between the two components, such that an ovary-determining signal produced by the XX component pre-empts the testis-determining action of the Y.

Observations on the functional organization of the ovarian balls ofMoniliformisandPolymorphus(Acanthocephala)

Parasitology ◽  
1974 ◽  
Vol 69 (3) ◽  
pp. 429-443 ◽  
Author(s):  
D. W. T. Crompton ◽  
P. J. Whitfield
Keyword(s):  
Electron Microscope ◽  
Functional Organization ◽  
Germ Line ◽  
Female Worm ◽  
Ovarian Tissue ◽  
Mature Female ◽  
Body Cavity ◽  
The Body ◽  
Initial Survey ◽  
Inner Region

By a variety of microscopical techniques, an initial survey has been made of the functional organization of ovarian balls from mature, inseminated femaleMoniliformis dubiusandPolymorphus minutus.On the basis of evidence from observations made with the transmission electron microscope, we have concluded that the ovarian ball consists of three components; these are two separate, multinucleate syncytia and a cellular zone. The inner region is considered to be an oogonial syncytium from which the germ-line cells arise to form the cellular zone. The oogonial syncytium and the cellular elements are embedded in a supporting syncytium which also forms the boundary of the ovarian ball. Details of the ultrastructure of these components, observations on fertilization and a hypothesis to account for the main events occurring in an acanthocephalan ovarian ball are also presented.Acanthocephalans are dioecious parasites which become sexually mature in the alimentary tract of vertebrates. After insemination, individual female worms begin to release embryonated eggs at rates which have been estimated to vary, on average, from 2000 per day in the case ofPolymorphus minutus(Crompton & Whitfield, 1968) to 260000 per day in the case ofMacracanthorhynchus hirudinaceus(Kates, 1944). Irrespective, however, of the species of acanthocephalan and the number of eggs produced, a most interesting mode of ovarian development and multiplication is believed to exist (see Bullock, 1969). Within the female worm, the primordial ovarian tissue gives rise to separate ovaries which are often termed ovarian balls. These in turn give rise to more ovarian balls and the process continues until large numbers have been formed. The ovarian balls of a mature female have no permanent attachment to the tissues of the worm. They are contained in the fluid of the body cavity either freely, or loosely constrained in large membranous chambers known as ligament sacs.Few investigations have been made into the structure and cytology of the ovarian balls of the Acanthocephala. Early observations on the histology of the germ-line constituents of ovarian balls were made by Hamann (1891), Kaiser (1893) and Meyer (1928), each of whom suggested that some of the developing oogonial stages were arranged in a syncytial manner. In a study of the embryology ofP. minutus.Nicholas & Hynes (1963) interpreted preparations of ovarian balls, which had been subjected to the Feulgen reaction, as indicative of syncytial tissue in the central region of the ball. They also recorded their uncertainty about whether an ovarian ball has a bounding membrane or not. More recently, Robinson (1964, 1965) described mitotic and meiotic divisions in oogonia and oocytes from ovarian balls ofMac. hirudinaceusandMoniliformis dubiusand Stranack (1972) included an electron micrograph of part of an ovarian ball ofPomphorhynchus laevisin a description of the nature of the egg envelopes of that species. In this paper, we present a general survey, based largely on evidence obtained with the electron microscope, of the functional organization of the ovarian balls of matureM. dubiusandP. minutus.

The internal anatomy of Typhlops schneider (Reptilia)

1960 ◽  
Vol 8 (2) ◽  
pp. 181 ◽  
Author(s):  
J Robb
Keyword(s):  
Connective Tissue ◽  
Reproductive Organs ◽  
Body Cavity ◽  
The Body ◽  
The Other ◽  
Internal Anatomy ◽  
Reproductive Systems ◽  
Male And Female ◽  
Connective Tissue Sheath ◽  
First Time

The internal anatomy of Typhlops shows a number of interesting features which support the hypothesis that the typhlopids are wrongly classified among the Ophidia, and that they should either be given subordinal rank, equivalent to the Sauria and the Serpentes, or be made an infra-order of the Sauria. The alimentary, vascular, respiratory, and reproductive systems are described in detail for the first time. The most striking peculiarities occur in the respiratory and reproductive systems. Unlike most snakes, Typhlops has two functional lungs, one occupying most of the anterior third of the body cavity, and the other smaller one lying immediately behind it. All the pulmonary blood vessels are well developed. The male reproductive organs are solid, grooved, protrusible structures, each of which is contained within a connective tissue sheath in the postanal region. These organs are unlike the hemipenes of any snake or lizard of which a description can be found. Both male and female animals possess a large cloaca1 gland in the postanal region. There are also several uncommon features in the alimentary and vascular systems.

Comparative morphology and descriptions of three new species of Teratocephalus from Canada

1969 ◽  
Vol 47 (5) ◽  
pp. 829-840 ◽  
Author(s):  
R. V. Anderson
Keyword(s):  
New Species ◽  
Comparative Morphology ◽  
The Body ◽  
Nominal Species ◽  
Reproductive Systems ◽  
Taxonomic Key ◽  
Three New Species ◽  
De Man

Three new species of soil-inhabiting nematodes, Teratocephalus decarinus, T. subvexus, and T. lirellus, are described. Contour and inclination of cephalic plicae, relative development of the cervical expansion, character of the body annules, number of longitudinal body ridges, and size of the metarhabdions are considered useful taxonomic characters. Morphology of the head, excretory and reproductive systems, and the cuticle is discussed and compared. All females have two uteri and bifurcated tail termini, which have not been reported previously for any known species in this genus. A taxonomic key to the nominal species is presented. T. demani Stefański, 1924 is transferred to Euteratocephalus Andrássy, 1958. T. terrestris, after De Coninck (1935), is regarded as different from T. terrestris (Bütschli, 1873) de Man, 1876 and is named T. deconincki.

Collagenous chitinophosphatic shell of the brachiopod Lingula

1994 ◽  
Vol 346 (1316) ◽  
pp. 223-266 ◽  
Keyword(s):  
Ultrastructural Level ◽  
The Body ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
Primary Layer ◽  
Median Septum ◽  
Fibrillar Collagens ◽  
Secondary Layer ◽  
Vertical Walls ◽  
Early Palaeozoic

The structure and composition of the shell of living Lingula have been studied in detail to provide a measure for evaluating the evolution of the lingulid shell since early Palaeozoic times. Four constituents are identifiable at ultrastructural level. Apatite, specifically the fluorapatite francolite, occurs as coated granules, up to lOnm in diameter, aggregated into spheroidal masses up to several microns in size, cylindroids up to 600 nm long and rare plates. Glycosaminoglycans (GAGs) are present throughout the shell as an elastic isotropic gel. Chitin is normally associated with a protein and is best seen under the scanning electron microscope after digestion of its associate by proteinases. As strands about 30 nm thick, chitin can form mats or be part of granular rods aligned as anastomosing ridges. Fibrillar collagens, with a periodicity of about 45 nm, occur mainly as sporadically developed mats throughout the body platform succession and as the core of the dorsal median septum. Elsewhere they appear sparingly as vertical and horizontal strands. At least ten proteins have been identified in the shell but it is not yet known which are covalently attached to GAGs, associated with the chitin or fabricated into membranes. The entire integument consists of: a periostracum, about 4 pm thick, made up of closely packed fibrous tubes with axial strands presumably of chitin; a primary layer, about 40 pm thick, composed mainly of GAGs; and a mineralized secondary layer of variable thickness. The secondary layer is a succession of isotopic and isochronic laminae with thicknesses in microns compared with areas frequently of several square millimetres. Compact laminae, composed of closely packed spheroidal aggregates of apatitic granules are succeeded: by botryoidal or walled laminae, in which apatitic aggregates form botryoidal masses or vertical walls in a GAGs matrix; or by rod and plate laminae with apatitic rods accreting into anastomosing ridges disposed transversely on the body platform and radially in peripheral regions. The preponderance of the botryoid and rod laminae in the body platform and of anastomosing ridges in the lateral areas of a valve respectively explains the complex patterns of c-axis orientation of apatite obtained by X-ray diffraction. Membranous laminae, consisting of chitinoproteinaceous membranes (and sporadic collagenous mats) in GAGs, occur throughout the succession; while stratified laminae, characterized by gentle inclined, alternating organic and apatitic units, each just over a micron thick, are especially well developed (with compact laminae) at the junction with the primary layer.

scholarly journals Memoirs: Studies in the Experimental Analysis of Sex

1912 ◽  
Vol s2-57 (228) ◽  
pp. 439-471
Author(s):  
GEOFFREY SMITH ◽  
EDGAR SCHUSTER
Keyword(s):  
Breeding Season ◽  
Peritoneal Cavity ◽  
Experimental Analysis ◽  
Fibrous Tissue ◽  
Testicular Tissue ◽  
Early Summer ◽  
The Body ◽  
Germinal Cells ◽  
Peritoneal Lining ◽  
Considerable Size

(1) The cyclical changes in the testes and thumb of male frogs are described. It is found that after the breeding season, although the outer papillated layers of the thumbpads are thrown off, yet the pads do not immediately become smooth, papillas of considerable size being present in the early summer months. The assumption of the perfectly smooth condition takes place gradually during the summer, and is due, not to a process of reduction, but to a proliferation of the epidermis which fills in the valleys between the papillae. (2) Transplantation of testes into other individuals, whether male or female (allo-transplantation), leads to the breaking-up and degeneration of the ripe spermatozoa and the testicular tissue, and its replacement by fibrous tissue, the greater part of which is derived from the host and invades the degenerate testis from the place of attachment to the host's body. Testes transplanted into the peritoneal cavity of another individual always become attached to the peritoneal lining and rapidly vascularised. Phagocytosis plays an important part in the absorption of the degenerate spermatozoa. (3) When the testes are simply severed from their connections in the body and left unattached in the peritoneal cavity of the same individual (auto-transplantation), they soon acquire new attachments and vascularisation. The ripe spermatozoa rapidly degenerate and are finally replaced by fibrous tissue, partly, at any rate, derived from the testis itself, but the spermatogonia of the peripheral tubules survive, and proliferate in an active manner. This survival of the germinal cells in the case of auto-transplantation never occurs in allo-transplantation.

Differentiation markers in the Drosophila ovary

Development ◽  
1984 ◽  
Vol 84 (1) ◽  
pp. 275-286
Author(s):  
Robert A. H. White ◽  
Norbert Perrimon ◽  
Walter J. Gehring
Keyword(s):  
Monoclonal Antibody ◽  
Wheat Germ ◽  
Germ Line ◽  
Anterior Part ◽  
Differentiation Markers ◽  
Ovarian Cell ◽  
Adult Ovary ◽  
Preferential Binding ◽  
Tunica Propria ◽  
Drosophila Ovary

A library of monoclonal antibodies, raised against imaginal discs of Drosophila melanogaster, was screened for binding to differentiation antigens in the adult ovary by immunofluorescence. Several lectins were similarly assayed. Two antibodies, DOV 1 and DOV 2, and wheat germ agglutinin exhibited binding which was restricted to particular stages of ovarian cell differentiation. DOV 2 also showed a marked preferential binding to the cell surface of germ line cells in the ovary. A differentiation of the portion of the tunica propria covering the anterior part of the germarium was revealed by the monoclonal antibody DOV 3. Another monoclonal antibody, DOV 4, identified a molecular specialization of the chorion at the tip of the micropyle. These markers should provide tools for the molecular analysis of oogenesis.

Ultrastructural localization of Sm28 GST protective antigen in Schistosoma mansoni adult worms

Parasitology ◽  
1996 ◽  
Vol 113 (4) ◽  
pp. 377-391 ◽  
Author(s):  
J. L. Liu ◽  
J. Fontaine ◽  
A. Capron ◽  
J. M. Grzych
Keyword(s):  
Schistosoma Mansoni ◽  
Protective Antigen ◽  
Ultrastructural Localization ◽  
Ultrastructural Level ◽  
Staining Intensity ◽  
Wide Distribution ◽  
Published Data ◽  
Glutathione S Transferase ◽  
Sustentacular Cells ◽  
Germinal Cells

SUMMARYThe localization of the 28 kDa Schistosoma mansoni glutathione S-transferase (Sm28 GST) has been investigated using immunohistochemistry and electron microscopy and the results compared with previously published data. This study confirms the wide distribution of this antigen in the parasite. In male and female worms, Sm28 GST is localized in the tegument, the parenchyma, the oesophageal epithelium and in genital organs. Sm28 GST was clearly detected in germinal and sustentacular cells. The decrease of staining intensity during the differentiation of germinal cells suggests a down-regulated expression of the molecule. At the ultrastructural level, this antigen was abundant in nuclei and less present in the cytoplasm. The marked heterogeneity observed in the staining of individual worms indicates that Sm28 GST seems to be closely associated with the parasite’s metabolism. The results are discussed in relation to the biological and protective functions of the protein.

The Superorganism

2020 ◽  
pp. 111-125
Author(s):  
Robert E. Page
Keyword(s):  
20Th Century ◽  
Social Insects ◽  
Germ Line ◽  
The Body ◽  
Early 20Th Century ◽  
Insect Societies ◽  
Real Entity ◽  
William Morton Wheeler

Insect societies have been likened to superorganisms since the early 20th century because they are organized around defense, nutrition, and reproduction, like our own bodies. Like individual organisms, they undergo development and separate the germ line (eggs and sperm in our case) from the body cells, the soma. In social insects, the germ line is sequestered in the reproductive individuals, while the body cells are the non-reproductive workers. The superorganism was proposed by William Morton Wheeler as a real entity but instead was used primarily as a metaphor, a structure for hanging analogies with human organisms and societies. Throughout the 20th century there were many twists and turns in the definition and use of the superorganism concept and many questions regarding its usefulness.

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