Histogenesis of lymphoid organs in larvae of the South African clawed toad, Xenopus laevis (Daudin)

Development ◽  
1969 ◽  
Vol 22 (2) ◽  
pp. 265-277
Author(s):  
Margaret J. Manning ◽  
John D. Horton
Keyword(s):  
Xenopus Laevis ◽  
South African ◽  
Lymphoid Tissue ◽  
Rana Catesbeiana ◽  
Neck Region ◽  
Lymphoid Organs ◽  
The Body ◽  
Lymph Glands ◽  
Branchial Region ◽  
Myeloid Tissue

Before embarking on a study of the lymphoid system of an amphibian larva, it is necessary to realize that lymphoid tissue may occur in many organs of the body and that in all immature vertebrates and in adult poikilotherms separation of lymphoid tissue from myeloid tissue is incomplete (Yoffey, 1960). Jordan (1938) reviewed the early work on the haemopoietic tissues of Amphibia. Cooper (1967 a, b) and Baculi & Cooper (1967) made a thorough investigation of the lymphomyeloid and lymphoepithelial organs of the bullfrog, Rana catesbeiana, in the branchial region of the larva and in the ventral neck region of the adult. In the larva they found three pairs of ventral cavity bodies and one pair of lymph glands; in the adult, propericardial bodies, procoracoid bodies, epithelial bodies and jugular bodies were present. Cooper (1967a) reviewed the literature on these organs and discussed their nomenclature.

Development and Organization of the Secondary and Tertiary Lymphoid Organs: Influence of Microbial and Food Antigens

2019 ◽  
Vol 19 (2) ◽  
pp. 128-135 ◽  
Author(s):  
Thea Magrone ◽  
Emilio Jirillo
Keyword(s):  
Vitamin A ◽  
Lymphoid Tissue ◽  
Vitamin A Deficiency ◽  
Lymphoid Organs ◽  
The Body ◽  
Lymphoid Cells ◽  
Host Cells ◽  
Lymphoid Tissues ◽  
Food Antigens

Background:Secondary lymphoid organs (SLO) are distributed in many districts of the body and, especially, lymph nodes, spleen and gut-associated lymphoid tissue are the main cellular sites. On the other hand, tertiary lymphoid organs (TLO) are formed in response to inflammatory, infectious, autoimmune and neoplastic events. </P><P> Developmental Studies: In the present review, emphasis will be placed on the developmental differences of SLO and TLO between small intestine and colon and on the role played by various chemokines and cell receptors. Undoubtedly, microbiota is indispensable for the formation of SLO and its absence leads to their poor formation, thus indicating its strict interaction with immune and non immune host cells. Furthermore, food antigens (for example, tryptophan derivatives, flavonoids and byphenils) bind the aryl hydrocarbon receptor on innate lymphoid cells (ILCs), thus promoting the development of postnatal lymphoid tissues. Also retinoic acid, a metabolite of vitamin A, contributes to SLO development during embryogenesis. Vitamin A deficiency seems to account for reduction of ILCs and scarce formation of solitary lymphoid tissue. </P><P> Translational Studies: The role of lymphoid organs with special reference to intestinal TLO in the course of experimental and human disease will also be discussed. </P><P> Future Perspectives: Finally, a new methodology, the so-called “gut-in-a dish”, which has facilitated the in vitro interaction study between microbe and intestinal immune cells, will be described.

COMPARATIVE EFFECTS OF THE OESTROGENS AND OTHER STEROID HORMONES ON SERUM LIPIDS AND PROTEINS IN XENOPUS LAEVIS DAUDIN

1969 ◽  
Vol 43 (1) ◽  
pp. 47-53 ◽  
Author(s):  
M. R. REDSHAW ◽  
B. K. FOLLETT ◽  
T. J. NICHOLLS
Keyword(s):  
Plasma Concentration ◽  
Xenopus Laevis ◽  
Steroid Hormones ◽  
South African ◽  
Calcium Binding ◽  
Serum Lipids ◽  
Response Curves ◽  
Yolk Formation ◽  
Log Linear ◽  
Relative Potencies

SUMMARY A comparison has been made between the effects of oestradiol-17β, oestrone, oestriol, progesterone, testosterone and cortisone on the plasma concentration of proteins and lipids in the South African clawed toad, Xenopus laevis Daudin. No major changes in the parameters studied were found with the non-oestrogenic steroids; only the three oestrogens induced the appearance in the plasma of a calcium-binding phospholipoprotein and esterified lipids associated with yolk formation. These results support the hypothesis that the oestrogens alone cause the vitellogenic response in oviparous vertebrates. Dose—response curves for oestradiol-17β, oestrone and oestriol were established for the effects on plasma protein, calcium, protein-bound phosphorus, phospholipid, lipid and cholesterol. The curves obtained were log.-linear over the range of doses employed (oestradiol-17β, 1–50 μg./day; oestrone, 4–100 μg./day; oestriol, 20–500 μg./day) with the exception of the cholesterol response to oestradiol. The relative potencies of the three oestrogens were compared for each of the plasma components measured. Oestradiol-17β was the most potent, being 3·9 times more active than oestrone and 13·7 times more active than oestriol.

Physiological function and neuromuscular recruitment in elite South African distance runners

2004 ◽  
Vol 1 (4) ◽  
pp. 261-271 ◽  
Author(s):  
Timothy D Noakes ◽  
Yolande XR Harley ◽  
Andrew N Bosch ◽  
Frank E Marino ◽  
Alan St Clair Gibson ◽  
...  
Keyword(s):  
South African ◽  
Exercise Physiology ◽  
The Body ◽  
Running Economy ◽  
Superior Performance ◽  
Black Athletes ◽  
Training Environment ◽  
Complex Biological System ◽  
Black African ◽  
Black South African

AbstractPhysiological studies of elite and sub-elite black South African runners show that these athletes are typically about 10–12 kg lighter than white athletes and that they are able to sustain higher exercise intensities for longer than white runners. Such superior performance is not a result of higher V O2max values and hence cannot be due to superior oxygen delivery to the active muscles during maximal exercise, as is predicted by the traditional cardiovascular/anaerobic/catastrophic models of exercise physiology. A marginally superior running economy is also unlikely to be a crucial determinant in explaining this apparent superiority. However, black athletes are able to sustain lower rectal and thigh, but higher mean skin, temperatures during exercise. Furthermore, when exercising in the heat, lighter black athletes are able to maintain higher running speeds than are larger white runners matched for running performance in cool environmental conditions. According to the contrasting theory that the body acts as a complex system during exercise, the superiority of black African athletes should be sought in an enhanced capacity to maintain homeostasis in all their inter-dependent biological systems despite running at higher relative exercise intensities and metabolic rates. In this case, any explanation for the success of East African runners will be found in the way in which their innate physiology, training, environment, expectations and genes influence the function of those parts of their subconscious (and conscious) brains that appear to regulate the protection of homeostasis during exercise as part of an integrative, complex biological system.

TISSUE DISTRIBUTION OF IMMUNOREACTIVE SOMATOSTATIN IN THE SOUTH AFRICAN CLAWED TOAD (XENOPUS LAEVIS)

1979 ◽  
Vol 80 (3) ◽  
pp. 407-408 ◽  
Author(s):  
B. SHAPIRO ◽  
M. SHEPPARD ◽  
S. KRONHEIM ◽  
B. L. PIMSTONE
Keyword(s):  
Xenopus Laevis ◽  
Tissue Distribution ◽  
South African ◽  
Rich Source ◽  
Gut Peptides ◽  
The South ◽  
The Brain

Immunoreactive somatostatin is present in the brain, gut and pancreas of the South African clawed toad, but is absent from the skin, a rich source of many other brain–gut peptides.

scholarly journals ‘The fact that she just looked at me…’ – Narrations on shame in South African workplaces

2017 ◽  
Vol 43 (0) ◽  
Author(s):  
Claude-Hélène Mayer ◽  
Rian Viviers ◽  
Louise Tonelli
Keyword(s):  
Mental Health ◽  
Higher Education ◽  
South African ◽  
Well Being ◽  
The Body ◽  
Theory And Practice ◽  
Work Context ◽  
Negative Effects ◽  
Managerial Implications ◽  
Health And Well Being

Orientation: Shame has been internationally researched in various cultural and societal contexts as well as across cultures in the workplace, schools and institutions of higher education. It is an emotional signal that refers to experienced incongruence of identity goals and the judgement of others.Research purpose: The purpose of this study was to focus on experiences of shame in the South African (SA) workplace, to provide emic, in-depth insights into the experiences of shame of employees.Motivation for the study: Shame in the workplace often occurs and might impact negatively on mental health and well-being, capability, freedom and human rights. This article aims at gaining some in-depth understanding of shame experiences in SA workplaces. Building on this understanding the aim is to develop awareness in Industrial and Organisational Psychologists (IOPs), employees and organisations to cope with shame constructively in addition to add to the apparent void in the body of knowledge on shame in SA workplaces.Research design, approach and method: An interpretative hermeneutical research paradigm, based on Dilthey’s modern hermeneutics was applied. Data were collected through semistructured interviews of 11 employees narrating their experiences from various workplaces, including the military, consulting organisations and higher education institutions. Content analysis was used for data analysis and interpretation.Main findings: The major themes around which shameful experiences evolved included loss of face, mistreatment by others, low work quality, exclusion, lifestyle and internalised shame on failure in the workplace. Shame is experienced as a disturbing emotion that impacts negatively on the self within the work context. It is also experienced as reducing mental health and well-being at work.Practical/managerial implications: SA organisations need to be more aware of shame in the workplace, to address the potential negative effects of shame on employees, particularly if they are not prepared to reframe shame into a constructively and positively used emotion. Safe spaces should be made available to talk about shame. Strategies should be applied to deal with shame constructively.Contribution/value-add: This article expands an in-depth understanding of shame from emic and culture-specific perspectives within SA workplaces. The findings are beneficial to IOPs and organisations to understand what shame is from the perspective of SA employees across cultural groups. The article thereby adds value to theory and practice, offering IOPs a deeper understanding of shame in the work context.

Integrative taxonomic methods reveal an incorrect synonymisation of the South African Pseudonereis podocirra (Schmarda) as the widespread Pseudonereis variegata (Grube) from Chile

2018 ◽  
Vol 32 (6) ◽  
pp. 1282 ◽  
Author(s):  
Jyothi Kara ◽  
Angus H. H. Macdonald ◽  
Carol A. Simon
Keyword(s):  
South Africa ◽  
South African ◽  
Species Delimitation ◽  
Haplotype Network ◽  
The Body ◽  
General Description ◽  
The South ◽  
Morphological Examination ◽  
Genetic Structuring ◽  
The Status

The nereidid Pseudonereis variegata (Grube, 1866) described from Chile includes 14 synonymised species from 10 type localities with a discontinuous distribution, but no taxonomic or molecular studies have investigated the status of this species outside Chile. Two synonymised species, Mastigonereis podocirra Schmarda, 1861 and Nereis (Nereilepas) stimpsonis Grube, 1866, were described from South Africa and investigated here using morphological examination. MtCOI species delimitation analyses and morphology were used to determine the status of P. variegata in South Africa. Morphological examination revealed that museum and freshly collected specimens from South Africa that conform to the general description of P. variegata are similar to M. podocirra and N. stimpsonis with respect to the consistent absence of homogomph spinigers in the inferior neuropodial fascicle, expanded notopodial ligules and the subterminal attachment of dorsal cirri in posterior parapodia. The synonymy of M. podocirra and N. stimpsonis as P. variegata are rejected and P. podocirra, comb. nov. is reinstated. Morphologically, Pseudonereis podocirra differed from specimens from Chile with regard to the numbers of paragnaths, the absence of homogomph spinigers and changes in parapodial morphology along the body. Independence of these species was further supported by genetic distances, automatic barcode gap discovery and multi-rate Poisson tree process species delimitation analyses of 77 mtCOI sequences. Haplotype network revealed no genetic structuring within the South African populations. http://zoobank.org/urn:lsid:zoobank.org:pub:F0B1A5AF-9CE9-4A43-ACCF-17117E1C2F21

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