The restrictive effect of early exposure to lithium upon body pattern in Xenopus development, studied by quantitative anatomy and immunofluorescence

Development ◽  
1988 ◽  
Vol 102 (1) ◽  
pp. 85-99 ◽  
Author(s):  
J. Cooke ◽  
E.J. Smith

We have carried out an anatomical study of Xenopus larval and gastrula stages resulting from treatment of synchronous early blastulae for brief periods with Li+. We confirm the proposal that such treatment causes a particular transformation, and partial elimination, of the normal body pattern. Coordinated restriction of pattern, without appreciable loss of cell number, is seen in all three germ layers. The distortion has been investigated by quantitative study of mesoderms at a standard stage, in relation to the normal fate map for mesoderm, and with the help of immunofluorescence on sections for somitic muscle and for blood. In the extreme syndrome, mesoderm arises from all around the blastula as usual, but is symmetrical and corresponds to that arising near the dorsal/anterior meridian of the normally specified egg or embryo with a large posterior subset of the normal pattern values thus missing. The effect is independent of any inhibition of archenteron formation or mesoderm migration (i.e. the cell mechanics of gastrulation) incurred by the treatment. It is also quite separate from a syndrome caused by more prolonged exposure to Li+ during gastrulation. A small, but distinctive, anterior pattern region is also not expressed and, anomalously in relation to their general nature, these forms differentiate considerable blood tissue. We consider the implications of some details of the pattern restriction for our understanding of interaction in the normal development and propose that the Li+ embryo is likely to be useful as a specific ‘differential screen’, in relation to the normal, during the search for those gene products that mediate initial regionalization of the body.

Development ◽  
1979 ◽  
Vol 53 (1) ◽  
pp. 269-289
Author(s):  
Jonathan Cooke

Morphological evidence is presented that definitive mesoderm formation in Xenopus is best understood as extending to the end of the neurula phase of development. A process of recruitment of cells from the deep neurectoderm layers into mesodermal position and behaviour, strictly comparable with that already agreed to occur around the internal blastoporal ‘lip’ during gastrula stages, can be shown to continue at the posterior end of the presumptive body pattern up to stage 20 (earliest tail bud). Spatial patterns of incidence of mitosis are described for the fifteen hours of development between the late gastrula and stage 20–22. These are related to the onset of new cell behaviours and overt cyto-differentiations characterizing the dorsal axial pattern,which occur in cranio-caudal and then medio-lateral spatial sequence as development proceeds. A relatively abrupt cessation of mitosis, among hitherto asynchronously cycling cells,precedes the other changes at each level in the presumptive axial pattern. The widespread incidence of cells still in DNA synthesis, anterior to the last mitoses in the posterior-to-anteriordevelopmental sequence of axial tissue, strongly suggests that cells of notochord and somites in their prolonged, non-cycling phase are G2-arrested, and thus tetraploid. This is discussed in relation to what is known of cell-cycle control in other situations. Best estimates for cell-cycle time in the still-dividing, posterior mesoderm of the neurula lie between 10 and 15 h. The supposition of continuing recruitment from neurectoderm can resolve an apparent discrepancy whereby total mesodermal cell number nevertheless contrives to double over a period of approximately 12 h during neurulation when most of the cells are leaving the cycle. Because of pre-existing evidence that cells maintain their relative positions (despite distortion)during the movements that form the mesodermal mantle, the patterns presented in this paper can be understood in two ways: as a temporal sequence of developmental events undergone by individual, posteriorly recruited cells as they achieve their final positions in the body pattern, or alternatively as a succession of wavefronts with respect to changes of cellstate, passing obliquely across the presumptive body pattern in antero-posterior direction. These concepts are discussed briefly in relation to recent ideas about pattern formation in growing systems.


Development ◽  
1985 ◽  
Vol 88 (1) ◽  
pp. 85-112
Author(s):  
Jonathan Cooke ◽  
John A. Webber

Xenopus embryos have been selected in which the second cleavage is occuring in a frontal plane, i.e one tending to lie at right angles to the prospective plane of bilateral symmetry for the body pattern. Some of these have been used to deduce a map of the disposition of materials for the normal mesodermal pattern (the normal ‘fate map’) by injecting blastomeres to found fluorescently marked clones from 4- to 32-cell stages. Other such 4-cell embryos have been separated into two isolates across this second cleavage; in fate-map terms, prospective dorsoanterior and posterior isolates. These have been allowed to develop to control axial larval stages, with examination of the time schedule of their gastrulation movements in relation to cofertilized whole controls. The patterns of mesoderm produced have been examined and interpreted in the light of quantitative knowledge about the normal pattern, and our current understanding of the map. A meaningful fate map exists for the egg material even at this early, essentially acellular stage, and it differs appreciably from what might have been expected in view of that traditionally shown for early gastrula stages. The patterns developed in the isolates show that at least in many eggs, widespread information that positively specifies material as to its body position is available from at most 1 h after the events that give rise to bilateral symmetry upon fertilization. This information usually leads to a mosaic development of the appropriate mesodermal part-pattern in dorsoanterior isolates, and frequently allows development that approximates to this in the reciprocal posterior part. Regulation, i.e. the replacement of removed information to specify a development more complete than the normal contribution in isolates, is not observed. The results suggest a revision of former claims for regulative ability in at least this amphibian embryo. They also imply that systems for ascribing position value (positional information) to early embryonic tissue can be diverse in dynamics, even among embryos whose body plans are obviously homologous as are those of vertebrates.


Development ◽  
1962 ◽  
Vol 10 (4) ◽  
pp. 530-562
Author(s):  
M. Enesco ◽  
C. P. Leblond

While the organs and tissues of the young rat are known to increase in size with age (Donaldson, 1924), little is known of the role played by the component cells in this increase. There is evidence that cells enlarge (Levi, 1906; Plenk, 1911) and new cells are added (Strasburger, 1893), but we do not know to what extent the enlargement and proliferation of the cells cause the growth of organs and tissues. The present work is an attempt to clarify this problem. In the past, the growth of organs and tissues has often been measured by weight gain (Donaldson, 1924). However, this approach might be misleading, since the body-weight may increase in the absence of growth, for instance as a result of fat-storage in old rats, of pregnancy in females, and even of changes in room temperature.


Development ◽  
1992 ◽  
Vol 115 (3) ◽  
pp. 745-753 ◽  
Author(s):  
V. F. Irish ◽  
I. M. Sussex

We have mapped the fate of cells in the Arabidopsis embryonic shoot apical meristem by irradiating seed and scoring the resulting clonally derived sectors. 176 white, yellow, pale green or variegated sectors were identified and scored for their position and extent in the resulting plants. Most sectors were confined to a fraction of a leaf, and only occasionally extended into the inflorescence. Sectors that extended into the inflorescence were larger, and usually encompassed about a third to a half of the inflorescence circumference. We also find that axillary buds in Arabidopsis are clonally related to the subtending leaf. Sections through the dry seed embryo indicate that the embryonic shoot apical meristem contains approximately 110 cells in the three meristematic layers prior to the formation of the first two leaf primordia. The histological analysis of cell number in the shoot apical meristem, in combination with the sector analysis have been used to construct a map of the probable fate of cells in the embryonic shoot apical meristem.


1963 ◽  
Vol 41 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Ronald M. Christie ◽  
Helen I. Battle

Larvae of the lamprey, Entosphenus lamottei (Le Sueur), and rainbow trout, Salmo gairdneri Richardson, were exposed to the sodium salt of 3-trifluormethyl-4-nitrophenol (TFM) in concentrations of 0.75 p.p.m., 3.00 p.p.m., and 6.00 p.p.m. Microscopic examination of changes induced in the gills, liver, cloacal region, and musculature were made on 7-micron sections stained with Harris' haematoxylin and Bowie's eosin, and in the gill region with periodic acid Schiff reagent. A comparison of the degree of the effects in the two species was made by planimetry of the vascular, cellular, and edematous areas from enlarged drawings of sections.Upon exposure to lethal concentrations of TFM, the body of the larval lamprey becomes distended at the pharyngeal level and heavy cords of mucus emerge from the external gill clefts. A deep red coloration is evident in the pharyngeal region consequent upon vasodilatation of the arterioles and capillaries of the gill filaments. Trout exhibit a similar vasodilatation of the gills together with increased mucous secretion. Edema in the connective tissue between the respiratory epithelium and the vascular endothelium is induced in both species. After prolonged exposure to TFM, the mucous cells in the lining of the branchial chamber and covering the tips of the gill filaments are actively discharging their secretions or completely spent.Certain effects induced by TFM in the larval lamprey are not evident in the trout. The cloacal region takes on a deep red coloration due to dilatation of the venous sinuses and the liver becomes reddish because of sinusoidal dilatation. Extensive edema of the fibrous connective tissue of the skeletal musculature is characteristically present. A slightly increased secretory activity of mucous-secreting cells may occur in the epidermis.With the techniques employed in this study, there was no evidence in either species of cytological or histological changes in the nervous tissue, cardiac musculature, notochord, alimentary canal (including the haemopoietic typhlosole of the lamprey), or mesonephros.


2017 ◽  
Vol 11 (1) ◽  
pp. 1321-1329
Author(s):  
Edie Benedito Caetano ◽  
Yuri da Cunha Nakamichi ◽  
Renato Alves de Andrade ◽  
Maico Minoru Sawada ◽  
Mauricio Tadeu Nakasone ◽  
...  

Introduction: This paper reports anatomical study of nature, incidence, innervation and clinical implications of Flexor Pollicis Brevis muscle (FPB). Material and Methods: The anatomical dissection of 60 limbs from 30 cadavers were performed in the Department of Anatomy of Medical School of Catholic University of São Paulo. Results: The superficial head of FPB has been innervated by the median nerve in 70% and in 30% it had double innervation. The deep head of FPB were absent in 14%, in 65%, occurred a double innervation. In 17.5% by deep branch of ulnar nerve and in 3.6% by recurrent branch of median nerve. Conclusion: The pattern of innervation more frequent in relationship to the flexor pollicis brevis muscle and should be considered as a normal pattern is that superficial head receives innervation of branches of median nerve and the deep head receives innervation of ulnar and median nerve.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Ovidiu-Dumitru Ilie ◽  
Emanuela Paduraru ◽  
Madalina-Andreea Robea ◽  
Ioana-Miruna Balmus ◽  
Roxana Jijie ◽  
...  

Background. As every organ within the body, the brain is also extremely susceptible to a plethora of noxious agents that change its chemistry. One component frequently found in current products against harmful species to crops is rotenone whose effect under prolonged exposure has been demonstrated to cause neurodegenerative disorders such as Parkinson’s disease. The latest reports have indeed revealed that rotenone promotes Parkinson’s in humans, but studies aiming to show congruent effects in zebrafish (Danio rerio) are lacking. Material and Methods. In this context, the aim of the present study was to demonstrate how chronic administration of rotenone for 3 weeks impairs the locomotor activity and sociability and induces oxidative stress in zebrafish. Results. There were no statistically significant differences following the analysis of their social interaction and locomotor tests ( p > 0.05 ). However, several exceptions have been noted in the control, rotenone, and probiotics groups when we compared their locomotor activity during the pretreatment and treatment interval ( p < 0.05 ). We further assessed the role of rotenone in disturbing the detoxifying system as represented by three enzymes known as superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA). Despite the fact that there were no statistically significant changes within SOD and GPx levels between the control group and rotenone, probiotics, and rotenone + probiotics ( p > 0.05 ), relevant changes have been observed between the analyzed groups ( p < 0.05 and p < 0.005 , respectively). On the other hand, significant differences ( p < 0.05 ) have been observed for MDA when we analyzed the data between the control group and the other three groups. Conclusions. Our results suggest that rotenone can be successfully used to trigger Parkinson’s disease-related symptomatology in zebrafish.


1962 ◽  
Vol 3 (2) ◽  
pp. 169-180 ◽  
Author(s):  
Forbes W. Robertson

1. Mass selection for both high- and low-ratio of wing to thorax length has been carried out on a population of Drosophila melanogaster. The response to selection was immediate and sustained. When the experiment was stopped after ten generations, the wing area in the two selected lines differed by about 30%. The heritability estimate worked out at 0·56 ± 0·08.2. Thorax length remained comparatively unchanged during selection nor was there any change in wing shape. There was some evidence of assymetry of response since there was a relatively greater change in favour of smaller rather than larger size.3. The tibia length of all pairs of legs showed correlated changes so that the lines with larger or smaller wing sizes had also larger and smaller legs.4. The normal allometric relation between wing and thorax length, associated with variation in body-size, apparently also changed, so that for a given change in thorax length there was a greater or smaller proportional change in wing size in the high- or low-ratio lines.5. The changes in relative wing size are due to changes in cell number.6. It is suggested that the genetic changes due to selection act in the early pupal period when the imaginal discs are undergoing differentiation and proliferation to form imaginal hypoderm and appendages.7. Tests of genetic behaviour failed to show any departure from additivity in crosses which involved the unselected population and the high-ratio line. But highly significant departures existed in the cross to the low-ratio line. Relatively smaller wing size behaves as largely recessive. Stability of the normal wing/thorax ratio involves dominance and probably also epistasis. The genetic properties of the relative size of the appendage are apparently similar to those which characterize body-size as a whole.8. It is suggested that selection provides a valuable tool for studying the constancy or lability of the growth patterns which determine morphology.


2007 ◽  
Vol 293 (2) ◽  
pp. R884-R893 ◽  
Author(s):  
Juan Fuentes ◽  
Christophe Haond ◽  
Pedro M. Guerreiro ◽  
Nádia Silva ◽  
Deborah M. Power ◽  
...  

Calcium regulation in sturgeon is of special interest because they are a representative of the ancient fishes possessing mainly cartilaginous skeletons and a supposedly low calcium demand. The present study aimed to characterize the effect of a chronic absence of dietary calcium and the effect of parathyroid hormone-related protein (PTHrPA) (1-34) ( 7 ) on calcium balance in juvenile sturgeon ( Acipenser naccarii). At rest, sturgeon juveniles are in net positive calcium balance, since whole body calcium uptake is significantly higher than efflux and calcium accumulates in the body. To study the importance of dietary calcium, the sturgeon were kept on a calcium-free diet for 8 wk. This manipulation impaired growth as measured by failure to gain weight or increase in length and indicates that dietary calcium is important for growth in sturgeon. An increased whole body calcium uptake partially compensated dietary calcium deficiency and was associated with increased gill chloride cell number in lamellae and filaments in parallel with increased gill Na+K+-ATPase activity. In addition, a single injection of piscine PTHrP(1-34) significantly increased whole body calcium uptake and decreased whole body calcium efflux. Administration of PTHrP significantly increased circulating plasma calcium 4–24 h postinjection. The increase in net calcium transport and increased plasma levels of calcium is consistent with the actions of a hypercalcemic factor. It would appear that the sturgeon rely on calcium for growth and tightly regulate calcium transport. The action in calcium balance is consistent with PTHrP acting as a hypercalcemic factor in sturgeon.


2015 ◽  
Vol 32 (02) ◽  
pp. 098-103
Author(s):  
E. Fontes ◽  
B. Precht ◽  
M. Babinski ◽  
R. Cisne

Abstract Introduction: The anatomical science has many stages in its history and different origins that makes it hard to define a universal symbol among anatomists. Discussion: Many anatomical schools have adopted the Leonardo Da Vinci's drawing called “Vitruvian Man” as the symbol of the modern anatomy. However, this draw brings a symmetric view of the body within the mathematical proportions of the segments. Nevertheless, the anatomical study element is not symmetric and has a single architecture with beautiful harmony among its components. This element, the cadaver is the biggest treasure of the anatomical science and depository of all truths. Conclusion: This current work represents a tribute to the dissected cadaver, concerning it immeasurable value to the anatomist and the traditional use of it in anatomy department pointing to the new perspectives for academic and artistic conceptions of the human body.


Sign in / Sign up

Export Citation Format

Share Document