Study of the development of the internal organs of the double malformations of Chironomus dorsalis by fixed and sectioned materials

Development ◽  
1970 ◽  
Vol 24 (2) ◽  
pp. 287-303
Author(s):  
Hideo Yajima
Keyword(s):  
Ventral Side ◽  
Dorsal Side ◽  
Second Step ◽  
Convex Side ◽  
Internal Organs ◽  
Flat Side ◽  
Internal Structures ◽  
Pole Cells ◽  
The One ◽  
Thoracic And Abdominal

The development of the internal structures was investigated by fixed sections of the ‘double cephalon’ and ‘double abdomen’ of Chironomus dorsalis. The cell proliferation that gives rise to ‘germ Anlage’ or embryonic rudiment begins, in the double cephalon, along the entire convex (ventral) side of the egg and, in the double abdomen, at both ends of the flat (dorsal) side. As a result, a single fused Anlage of the double cephalon appears along the entire convex side of the egg and two germ Anlagen of the double abdomen appear at both ends of the flat side. During the formation of the germ band, both the posteriormost part of the double cephalon which lies at the middle of the convex side of the egg and the anteriormost part of the double abdomen which is located at the middle of the convex side, fail to differentiate and later degenerate. In each of the duplicated heads of double cephalon, cephalic segments anterior to the first maxillary segment are formed, but the thoracic and abdominal segments are entirely missing. In each half of the double abdomen, eight abdominal segments posterior to the second abdominal segment are produced and the cephalic and thoracic segments are omitted altogether. The two pairs of mid-gut rudiment from both halves of the double cephalon are temporarily united but they break apart by the end of the blastokinesis. When the two pairs of mid-gut rudiment from both halves of the double abdomen meet, they remain fused with each other, being surrounded by the visceral mesodermal cells in the normal way, and develop into the mid-gut epithelium. In the double malformations, the pole cells are contained in only one member of the duplicated structures. The pole cells of the double cephalon develop into the tetra-nucleate state (Hasper's second step), but they fail to fuse to form tte gonad. In the double abdomen, the gonad develops in the one abdomen containing the pole colls and no replacement occurs in the sister abdomen without the pole cells. The embryonic envelopes of the double cephalon do no' retract into the interior of the embryo, while they do in the normal way in the double abdomen. The double cephalon can never hatch but the double abdon en can emerge.

scholarly journals II. Preliminary note on the apex of the leaf in Osmunda and Todea . (From the Jodrell Laboratory, Royal Gardens, Kew.)

1883 ◽  
Vol 36 (228-231) ◽  
pp. 442-443
Keyword(s):  
Apical Cell ◽  
Ventral Side ◽  
Dorsal Side ◽  
Intermediate Step ◽  
Preliminary Note ◽  
Young Leaves ◽  
The Difference ◽  
Mode Of Development ◽  
Marginal Cells ◽  
The One

It has long been accepted, in accordance with the investigations of Sadebeck, that there is at the apex of the young leaf of the fern a two-sided, wedge-shaped, apical cell, and that, after this cell has lost its identity by periclinal, and subsequently by anticlinal divisions, the growth of the leaf is continued at the margin by the persistent activity of a linear series of marginal cells. It is true that this is the mode of development of many fern-leaves, but, as my observations show, it does not apply for all cases, while those exceptional cases are particularly interesting as occupying an intermediate position in this, as also in other, respects between the true ferns, on the one hand, and the Marathaceæ and Cycadeæ on the other. It is among the Osmundaceæ that these exceptional cases occur. In the young leaves of Todea superba and of Osmunda cinnamomea it was found that the apex is occupied by a well-marked, three-sided , conical, apical cell, from the three sides of which, segments are cut off in regular succession, as at the apex of the stem of Equisetum . The apical cell is so placed that one side faces the ventral side of the leaf, while the remaining two sides are obliquely disposed with regard to the dorsal side of the leaf. No clearly marked marginal series of persistently active cells have been found, giving rise to the pinnæ, as is stated to be the case for the typical ferns. Further, there appears to be no strict relation between the points of origin of the pinnæ and the segments cut off from the apical cell. The pinnæ arise in acropetal order. In itself no great importance is to be attached to the difference between a three-sided and a two-sided apical cell. For example, it has been clearly shown in a paper by Treub, on the vegetative organs of Selaginella Martensii , that the two forms of apical cell are to be found on different shoots of the same species. But in the case of the leaf of the fern, the whole development, as described by Sadebeck and by Ruy, is so closely connected with the‘existence of a two-sided cell that a departure from that arrangement is to be regarded as of more importance than would otherwise be due to it, and it appears to me to supply an intermediate step towards the more complex leaf of the Marathaceæ and Cycadeæ .

scholarly journals The geometry of insect pairing

1922 ◽  
Vol 94 (656) ◽  
pp. 1-11 ◽  
Keyword(s):  
Median Plane ◽  
Bilateral Symmetry ◽  
Ventral Side ◽  
Dorsal Side ◽  
The Body ◽  
Anal Orifice ◽  
The One ◽  
Special Points ◽  
Asymmetrical Condition ◽  
Axial Twist

In insects bilateral symmetry is practically universal, except in some minor matters, as, for example, the slight overlap of the elytra exhibited by many beetles. In the females the symmetrical condition may be taken to be almost universal, but the males in certain families exhibit asymmetry, which in some cases is very extreme, in the terminal segments of the abdomen. It is with this condition that the present paper deals, and the simplest course to pursue is, first to state the case as shown by some species of Diptera, that being the Order most familiar to the author and one in which an asymmetrical condition is comparatively common, then to outline a possible explanation of the phenomenon, in the course of which certain terms will be defined in order to clear the ground of existing ambiguities. Certain statements made in the course of the argument will then be justified as far as possible, and, finally, a few special points will be discussed. In most insects, excluding such aberrant forms as the dragon-flies, the genital tube opens on the under side of the 9th abdominal segment, and the anal orifice is in the 10th. Let us trace a line in the vertical median plane of the insect, beginning on the dorsal side of the abdomen and proceeding round to the ventral side. On such a peregrination we shall first encounter the anal orifice and subsequently the genital one; this is true for all females and for most males, but there are some remarkable exceptions. Thus, it was shown by Snodgrass that in the Asilid genera Dascillis and Laphria a different condition exists. On referring to the figures in that paper, it will be seen that on tracing such a line round the insect in its median plane the genital orifice is met before the anal one ; the hypopygium is then said to be “inverted.” The term “hypopygium” will be used for the combination of the 9th and 10th segments, which are commonly fused into a single complex in flies, so that no movement of the one segment relative to the other is possible, and the two segments must always behave kinematically as a single body. This inversion is produced by the presence of a twist of 180° about the main axis of the body between the 6th segment and the hypopygium; the 8th segment is quite unsymmetrieal and has an axial twist of about 150°; the hypopygium has the complete twist of 180°, but nevertheless it is practically symmetrical about the median plane which still bisects it. The result of this twist is to produce a true asymmetry, although it may not be very apparent on casual examination; in fact, not until the relative positions of the orifices are looked into.

scholarly journals The Mutation masculinizer (man) Defines a Sex-Determining Gene With Maternal and Zygotic Functions in Musca domestica L.

Genetics ◽  
1997 ◽  
Vol 145 (1) ◽  
pp. 173-183 ◽  
Author(s):  
R Schmidt ◽  
M Hediger ◽  
R Nöthiger ◽  
A Dübendorfer
Keyword(s):  
Musca Domestica ◽  
Maternal Effect ◽  
Dominant Factor ◽  
Loss Of Function ◽  
New Mutation ◽  
Yolk Proteins ◽  
Hypomorphic Allele ◽  
Internal Structures ◽  
Primary Signal ◽  
Pole Cells

In Musca domestica, the primary signal for sex determination is the dominant factor M, which is assumed to regulate a postulated female-determining gene F. Presence of M prevents expression of F so that male development ensues. In the absence of M, F can become active, which dictates the female pathway. The existence of F is inferred from FD, a dominant factor that is epistatic to M. We describe a new mutation masculinizer, which has all the properties expected for a null or strongly hypomorphic allele of F: (1) it maps to the same chromosomal location as FD, (2) homozygous man/man animals develop as males, (3) homozygous man/man clones generated in man/+ female larvae differentiate male structures, (4) man has a sex-determining maternal effect. About a third of the morphological males synthesize yolk proteins, which indicates that they are intersexual in internal structures. The maternal effect of man is complete in offspring that derive from homozygous man/man pole cells transplanted into female hosts. In this case, all man/+ progeny become fertile males that do not produce yolk proteins. A sex-determining maternal effect has previously been demonstrated for FD. Like F, maternal man  + is needed for zygotic man  + to become active, providing further evidence that man is a loss-of-function allele of F.

scholarly journals Gravity determines the direction of nerve roots sedimentation in the lumbar spinal canal

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Jun Yang ◽  
Zhiyun Feng ◽  
Nian Chen ◽  
Zhenhua Hong ◽  
Yongyu Zheng ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Mr Imaging ◽  
Spinal Canal ◽  
Ventral Side ◽  
Lateral Position ◽  
Dorsal Side ◽  
Mr Images ◽  
Nerve Roots ◽  
Cross Sectional ◽  
Dural Sac

Abstract Objectives To investigate the role of gravity in the sedimentation of lumbar spine nerve roots using magnetic resonance (MR) imaging of various body positions. Methods A total of 56 patients, who suffered from back pain and underwent conventional supine lumbar spine MR imaging, were selected from sanmen hospital database. All the patients were called back to our hospital to perform MR imaging in prone position or lateral position. Furthermore, the sedimentation sign (SedSign) was determined based on the suspension of the nerve roots in the dural sac on cross-sectional MR images, and 31 cases were rated as positive and another 25 cases were negative. Results The mean age of negative SedSign group was significantly younger than that of positive SedSign group (51.7 ± 8.7 vs 68.4 ± 10.5, P < 0.05). The constitutions of clinical diagnosis were significantly different between patients with a positive SedSign and those with a negative SedSign (P < 0.001). Overall, nerve roots of the vast majority of patients (48/56, 85.7%) subsided to the ventral side of the dural sac on the prone MR images, although that of 8 (14.3%) patients remain stay in the dorsal side of dural sac. Nerve roots of only one patient with negative SedSign did not settle to the ventral dural sac, while this phenomenon occurred in 7 patients in positive SedSign group (4% vs 22.6%, P < 0.001). In addition, the nerve roots of all the five patients subsided to the left side of dural sac on lateral position MR images. Conclusions The nerve roots sedimentation followed the direction of gravity. Positive SedSign may be a MR sign of lumbar pathology involved the spinal canal.

scholarly journals An Automated Method for the Quantification and Fractal Analysis of Immunostaining

2004 ◽  
Vol 26 (3) ◽  
pp. 125-134
Author(s):  
Armin Gerger ◽  
Patrick Bergthaler ◽  
Josef Smolle
Keyword(s):  
Fractal Analysis ◽  
Quantitative Description ◽  
Fractal Dimensionality ◽  
Texture Features ◽  
Second Step ◽  
Digital Information ◽  
Automated Method ◽  
Reliable Classification ◽  
The One

Aims. In tissue counter analysis (TCA) digital images of complex histologic sections are dissected into elements of equal size and shape, and digital information comprising grey level, colour and texture features is calculated for each element. In this study we assessed the feasibility of TCA for the quantitative description of amount and also of distribution of immunostained material. Methods. In a first step, our system was trained for differentiating between background and tissue on the one hand and between immunopositive and so‐called other tissue on the other. In a second step, immunostained slides were automatically screened and the procedure was tested for the quantitative description of amount of cytokeratin (CK) and leukocyte common antigen (LCA) immunopositive structures. Additionally, fractal analysis was applied to all cases describing the architectural distribution of immunostained material. Results. The procedure yielded reproducible assessments of the relative amounts of immunopositive tissue components when the number and percentage of CK and LCA stained structures was assessed. Furthermore, a reliable classification of immunopositive patterns was found by means of fractal dimensionality. Conclusions. Tissue counter analysis combined with classification trees and fractal analysis is a fully automated and reproducible approach for the quantitative description in immunohistology.

The Means and Mode of Salvation: A Hermeneutical Proposal for Clarifying Pauline Soteriology

2007 ◽  
Vol 29 (2) ◽  
pp. 203-222
Author(s):  
Peter Frick
Keyword(s):  
Second Step ◽  
Human Response ◽  
The One

AbstractThe objective of this study is to answer the question "What is the cause of salvation?" according to Paul. The argument is that just as Philo understood cause in an Aristotelian sense of the multiplicity of causes (formal, material, efficient and final) as constituting one overarching cause—what is here called the "means" of salvation—so, too, Paul implicitly assumes that the one cause or "means" of salvation consists in various causes. A second step shows how the "means" of salvation corresponds to faith as the "mode" of salvation. In nuce, the "means" of salvation is the initiative of God and the "mode" of salvation is the human response to that divine initiative.

Six new species of Archimonocelididae Meixner, 1938 (Platyhelminthes, Proseriata) from the Pacific, with proposal of a new genus

Zootaxa ◽  
2021 ◽  
Vol 4965 (3) ◽  
pp. 515-528
Author(s):  
MARCO CURINI-GALLETTI ◽  
ERNEST R. SCHOCKAERT
Keyword(s):  
New Species ◽  
New Genus ◽  
South Australia ◽  
Ventral Side ◽  
Copulatory Organ ◽  
Dorsal Side ◽  
The Pacific ◽  
Eastern Australia ◽  
The Pacific Ocean ◽  
The Caribbean

The genus Tajikacelis n. gen. is introduced for species of Archimonocelididae (Proseriata) characterized by the lack of atrial spines in the copulatory organ and by the opening of the seminal vesicles into the prostate vesicle at its ventral side. Six new species from the Pacific Ocean are ascribed to the new genus; they may be distinguished by features of the genital systems and the morphology of their copulatory stylets. T. tajikai n. sp. (type species of the new genus) and T. macrostomoides n. sp., both from eastern Australia, have a long tubular stylet. In T. macrostomoides n. sp., the stylet is more curved, bending to 180°, and has a narrower basis compared to that of T. tajikai n. sp. In T. artoisi n. sp., from Hawai’i, and T. nematoplanoides n. sp., from South Australia, the stylet is shaped as a truncated cone, with a broad, oblique proximal opening and a very short tubular part. T. artoisi n. sp. is distinct for the much stronger thickening of the dorsal side of the stylet, and for the different shape of the proximal opening. In T. acuta n. sp. and T. truncata n. sp., from West Panama, the tubular stylet is comparatively short; the two species differ for the shape of the distal opening, produced into a sharp spike in T. acuta n. sp., and square-ended in T. truncata n. sp.. Two species previously described in the genus Archimonocelis are transferred to Tajikacelis n. gen.: T. itoi Tajika, 1981 from Japan and T. keke Martens and Curini-Galletti, 1989 from Sulawesi (Indonesia). The taxonomic position of the problematic Archimonocelis glabrodorsata Martens and Curini-Galletti, 1989 from the Caribbean is discussed. The relationships of and within the genus Tajikacelis n. gen. are discussed and compared with recent results based on DNA studies. 

scholarly journals Atypical, ventro-ventral copulation position in aphids of the genus Stomaphis Walker, 1870 (Insecta, Hemiptera)

2014 ◽  
Vol 83 (3) ◽  
pp. 177-183 ◽  
Author(s):  
Łukasz Depa ◽  
Mariusz Kanturski ◽  
Artur Taszakowski ◽  
Karina Wieczorek
Keyword(s):  
Dominant Role ◽  
Mate Guarding ◽  
Ventral Side ◽  
Dorsal Side ◽  
Ecological Niches ◽  
Ventral Part ◽  
Large Tree ◽  
Mutualistic Relationship ◽  
Competitive Behaviour ◽  
Female Abdomen

Firm matching of genitals during copulation is of critical importance to effective insemination and thus, gene flow. During the evolution of insects, an effective position during copulation promoted higher fecundity through control over the act of mating or elimination of competitors. Usually during insect copulation, either twisting or flexing of the male abdomen occurs, and genitals remain symmetrically or asymmetrically disposed following changes in the mating position. However, it is always the dorsal side of the male genitalia that makes contact with the ventral side of female abdomen. Here we present the unusual case of a ‘belly-to-belly’ copulation, with symmetrically positioned male genitals and no twisting of the abdomen. During the mating of two species in the Stomaphis genus of large, tree dwelling aphids, the dwarfish male is attached to the underside of the female, with the ventral part of its genitals contacting the ventral part of female abdomen, and the aedeagus effectively inserted into the female genital organs. Interestingly, congeneric species do not exhibit this sort of mating, but differences in the genital plates of females, between species, may play an important role. These observations raise many questions concerning the possible dominant role of the female during mating and later, during mate guarding by male, which can lead to monandry in this generally polyandrous group of insects. It is possible that this sort of mating is either an adaptation to the competitive behaviour of other males or a consequence of the obligatory mutualistic relationship with ants, and the adaptation to specialised ecological niches enforced by this relationship. If ants do influence the mating habits of Stomaphis then it is possible that speciation in this group of insects, and phytophagous insects generally, is partially driven by their relationship with ants.

scholarly journals The changing use of the ovipositor in host shifts by ichneumonid ectoparasitoids of spiders (Hymenoptera, Ichneumonidae, Pimplinae)

Parasite ◽  
2018 ◽  
Vol 25 ◽  
pp. 17 ◽  
Author(s):  
Keizo Takasuka ◽  
Niclas R. Fritzén ◽  
Yoshihiro Tanaka ◽  
Rikio Matsumoto ◽  
Kaoru Maeto ◽  
...  
Keyword(s):  
Ventral Side ◽  
Middle Part ◽  
Dorsal Side ◽  
Physical Damage ◽  
Host Shifts ◽  
Ovipositor Morphology

Accurate egg placement into or onto a living host is an essential ability for many parasitoids, and changes in associated phenotypes, such as ovipositor morphology and behaviour, correlate with significant host shifts. Here, we report that in the ichneumonid group of koinobiont spider-ectoparasitoids (“polysphinctines”), several putatively ancestral taxa (clade I here), parasitic on ground-dwelling RTA-spiders (a group characterised by retrolateral tibial apophysis on male palpal tibiae), lay their eggs in a specific way. They tightly bend their metasoma above the spider’s cephalothorax, touching the carapace with the dorsal side of the ovipositor apically (“dorsal-press”). The egg slips out from the middle part of the ventral side of the ovipositor and moves towards its apex with the parted lower valves acting as rails. Deposition occurs as the parasitoid draws the ovipositor backwards from under the egg. Oviposition upon the tough carapace of the cephalothorax, presumably less palatable than the abdomen, is conserved in these taxa, and presumed adaptive through avoiding physical damage to the developing parasitoid. This specific way of oviposition is reversed in the putatively derived clade of polysphinctines (clade II here) parasitic on Araneoidea spiders with aerial webs, which is already known. They bend their metasoma along the spider’s abdomen, grasping the abdomen with their fore/mid legs, pressing the ventral tip of the metasoma and the lower valves of the ovipositor against the abdomen (“ventral-press”). The egg is expelled through an expansion of the lower valves, which is developed only in this clade and evident in most species, onto the softer and presumably more nutritious abdomen.

PS01.191: LAPAROSCOPIC TRANSHIATAL LOWER MEDIASTINAL LYMPHADENECTOMY FOR ESOPHAGOGASTRIC JUNCTIONAL CANCER: THE INFRACARDIAC BURSA AS A LANDMARK

2018 ◽  
Vol 31 (Supplement_1) ◽  
pp. 104-104
Author(s):  
Yasunori Kurahashi ◽  
Tatsuro Nakamura ◽  
Rie Ozawa ◽  
Yasutaka Nakanishi ◽  
Hirotaka Niwa ◽  
...  
Keyword(s):  
Lymph Node ◽  
Esophagogastric Junction ◽  
Conflicts Of Interest ◽  
Ventral Side ◽  
Dorsal Side ◽  
Node Dissection ◽  
Mediastinal Lymphadenectomy ◽  
Operating Field ◽  
Esophagogastric Junction Cancer ◽  
The Right

Abstract Background Esophagogastric junction cancer has been increasing recently. As a result, opportunities to perform transhiatal lower mediastinal lymphadenectomy are also increasing. Laparoscopic surgery is useful because the operating field of this site is too deep and narrow to perform laparotomy. But the anatomy of this area is not sufficiently clarified, and since there are few structures as landmarks, it is difficult to set the range and depth of lymph node dissection. Methods We have been verifying anatomically and embryologically the infracardiac bursa (ICB) identified as a closed lumen between the esophagus and the right crus of the diaphragm during an operation. We standardized the procedure of transhiatal lower mediastinal lymphadenectomy setting several landmarks including ICB. Results In transhiatal lower mediastinal lymphadenectomy, it is possible to do a precise lymphadenectomy by setting several landmarks including the ICB and standardizing each procedure on the ventral side, dorsal side, and both sides of the esophagus. In the case of advanced cancer which invades organs around the hiatus, it is difficult to perform routine dissection by using the infracardiac bursa or the dissectable layer. Understanding of the anatomy of this area will support the safe and precise lymphadenectomy. Conclusion In this presentation, we will show the procedure of transhiatal lower mediastinal lymphadenectomy using the ICB as a landmark. Disclosure All authors have declared no conflicts of interest.

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