The control of foot formation in transplantation experiments with hydra viridis

1975 ◽  
Vol 50 (1) ◽  
pp. 87-105 ◽  
Author(s):  
Joel E. Cohen ◽  
Harry K. MacWilliams
Keyword(s):  
Transplantation Experiments ◽  
Hydra Viridis

Ultrastructural Changes of the Symbiotic Chlorella-Like Alga Isolated from Hydra Viridis

1982 ◽  
Vol 40 ◽  
pp. 320-321
Author(s):  
K.W. Lee ◽  
R.H. Meints ◽  
D. Kuczmarski ◽  
J.L. Van Etten
Keyword(s):  
Time Course ◽  
Reciprocal Cross ◽  
Ultrastructural Level ◽  
Ultrastructural Changes ◽  
Symbiotic Relationship ◽  
Cell Recognition ◽  
Green Hydra ◽  
Different Strains ◽  
Hydra Viridis

The physiological, biochemical, and ultrastructural aspects of the symbiotic relationship between the Chlorella-like algae and the hydra have been intensively investigated. Reciprocal cross-transfer of the Chlorellalike algae between different strains of green hydra provide a system for the study of cell recognition. However, our attempts to culture the algae free of the host hydra of the Florida strain, Hydra viridis, have been consistently unsuccessful. We were, therefore, prompted to examine the isolated algae at the ultrastructural level on a time course.

It takes all kinds: heterogeneity among satellite cells and fibro-adipogenic progenitors during skeletal muscle regeneration

Development ◽  
2021 ◽  
Vol 148 (21) ◽  
Author(s):  
Brittany C. Collins ◽  
Gabrielle Kardon
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cells ◽  
Regenerative Process ◽  
Skeletal Muscle Regeneration ◽  
Anatomical Location ◽  
Muscle Stem Cells ◽  
Functional Consequences ◽  
Transplantation Experiments ◽  
Complete Regeneration ◽  
Vertebrate Skeletal Muscle

ABSTRACT Vertebrate skeletal muscle is composed of multinucleate myofibers that are surrounded by muscle connective tissue. Following injury, muscle is able to robustly regenerate because of tissue-resident muscle stem cells, called satellite cells. In addition, efficient and complete regeneration depends on other cells resident in muscle – including fibro-adipogenic progenitors (FAPs). Increasing evidence from single-cell analyses and genetic and transplantation experiments suggests that satellite cells and FAPs are heterogeneous cell populations. Here, we review our current understanding of the heterogeneity of satellite cells, their myogenic derivatives and FAPs in terms of gene expression, anatomical location, age and timing during the regenerative process – each of which have potentially important functional consequences.

Autonomy and non-autonomy in Drosophila mesoderm determination and morphogenesis

Development ◽  
1994 ◽  
Vol 120 (4) ◽  
pp. 853-859 ◽  
Author(s):  
M. Leptin ◽  
S. Roth
Keyword(s):  
Cell Shape ◽  
Shape Change ◽  
Developmental Program ◽  
Cell Shape Change ◽  
Ventral Furrow ◽  
Large Numbers ◽  
The Individual ◽  
Mutant Cells ◽  
Transplantation Experiments ◽  
Shape Changes

The mesoderm in Drosophila invaginates by a series of characteristic cell shape changes. Mosaics of wild-type cells in an environment of mutant cells incapable of making mesodermal invaginations show that this morphogenetic behaviour does not require interactions between large numbers of cells but that small patches of cells can invaginate independent of their neighbours' behaviour. While the initiation of cell shape change is locally autonomous, the shapes the cells assume are partly determined by the individual cell's environment. Cytoplasmic transplantation experiments show that areas of cells expressing mesodermal genes ectopically at any position in the egg form an invagination. We propose that ventral furrow formation is the consequence of all prospective mesodermal cells independently following their developmental program. Gene expression at the border of the mesoderm is induced by the apposition of mesodermal and non-mesodermal cells.

scholarly journals Dermal macrophages set pain sensitivity by modulating tissue NGF levels through SNX25–Nrf2 signaling

2021 ◽  
Author(s):  
Tatsuhide Tanaka ◽  
Hiroaki Okuda ◽  
Yuki Terada ◽  
Ayami Isonishi ◽  
Masahiro Kitabatake ◽  
...  
Keyword(s):  
Pain Sensitivity ◽  
Pain Behavior ◽  
Mrna Synthesis ◽  
Pain Sensation ◽  
Key Factors ◽  
Transgenic Mouse Line ◽  
Sorting Nexin ◽  
Peripheral Neurons ◽  
Peripheral Sensory ◽  
Transplantation Experiments

Abstract Crosstalk between peripheral neurons and immune cells plays important roles in pain sensation. We identified sorting nexin 25 (Snx25) as a pain-modulating gene in a transgenic mouse line with reduced pain behavior. Snx25 conditional-KO (cKO) in monocyte/macrophage-lineage cells but not in the peripheral sensory neurons reduced pain responses in both normal and neuropathic conditions. Cross transplantation experiments of bone marrows between cKO and wild type (WT) mice revealed that cKO macrophages caused dull phenotype in WT mice and WT macrophages in turn increased pain behavior in cKO mice. SNX25 in dermal macrophages enhances NGF (one of the key factors in pain sensation) production by inhibiting ubiquitin-mediated degradation of Nrf2, a transcription factor that activates Ngf mRNA synthesis. We conclude that dermal macrophages set pain sensitivity by producing and secreting NGF into the dermis in addition to their host defense functions.

scholarly journals UTERINE ADENOMATA IN THE RABBIT

1938 ◽  
Vol 67 (5) ◽  
pp. 691-708 ◽  
Author(s):  
Harry S. N. Greene ◽  
John A. Saxton
Keyword(s):  
Present Report ◽  
Pathological Study ◽  
Serial Transfer ◽  
Continuous Growth ◽  
The Past ◽  
Tumor Bearing ◽  
Uterine Mucosa ◽  
Intraocular Transplantation ◽  
Transplantation Experiments ◽  
Uterine Fundus

83 cases of an adenomatous tumor of the uterine mucosa have been observed in a colony of rabbits during the past 4 years The results of a clinical and pathological study of the tumor, together with a description of transplantation experiments are included in the present report. The clinical histories of tumor bearing animals are similar in all cases. Discovery of the tumor is preceded by a long period of reproductive disturbance, and its subsequent course is one of slow, continuous growth which has terminated in death with metastasis in all animals held under observation for longer than 1 year. Microscopically, the tumor shows an atypical alveolar structure, and its characteristics closely resemble those of an adenocarcinoma of the uterine fundus in women. Pathological changes similar to those observed in mice after treatment with estrogenic substances occur in the thyroid, suprarenal, pituitary and mammary glands. Intraocular transplantation of the tumor has been successful, and at the present time the growth has been carried through 6 generations by serial transfer.

scholarly journals Observations and experiments on regeneration in Hydra viridis

1901 ◽  
Vol 13 (1-2) ◽  
pp. 135-178 ◽  
Author(s):  
Helen Bean King
Keyword(s):  
Hydra Viridis

Algal endosymbiosis in brown hydra: host/symbiont specificity

1986 ◽  
Vol 86 (1) ◽  
pp. 273-286 ◽  
Author(s):  
M. Rahat ◽  
V. Reich
Keyword(s):  
Ecological Factors ◽  
Vacuolar Membrane ◽  
Physiological Strain ◽  
Free Living ◽  
Daughter Cells ◽  
Green Hydra ◽  
Endodermal Cells ◽  
Hydra Viridis ◽  
Algal Distribution

Host/symbiont specificity has been investigated in non-symbiotic and aposymbiotic brown and green hydra infected with various free-living and symbiotic species and strains of Chlorella and Chlorococcum. Morphology and ultrastructure of the symbioses obtained have been compared. Aposymbiotic Swiss Hydra viridis and Japanese H. magnipapillata served as controls. In two strains of H. attenuata stable hereditary symbioses were obtained with Chlorococcum isolated from H. magnipapillata. In one strain of H. vulgaris, in H. oligactis and in aposymbiotic H. viridis chlorococci persisted for more than a week. Eight species of free-living Chlorococcum, 10 symbiotic and 10 free-living strains of Chlorella disappeared from the brown hydra within 1–2 days. In H. magnipapillata there was a graded distribution of chlorococci along the polyps. In hypostomal cells there were greater than 30 algae/cell while in endodermal cells of the mid-section or peduncle less than 10 algae/cell were found. In H. attenuata the algal distribution was irregular, there were up to five chlorocci/cell, and up to 20 cells/hydra hosted algae. In the dark most cells of Chlorococcum disappeared from H. magnipapillata and aposymbiotic hydra were obtained. Chlorococcum is thus an obligate phototroph, and host-dependent heterotrophy is not required for the preservation of a symbiosis. The few chlorococci that survived in the dark seem to belong to a less-demanding physiological strain. In variance with known Chlorella/H. viridis endosymbioses the chlorococci in H. magnipapillata and H. attenuata were tightly enveloped in the vacuolar membrane of the hosting cells with no visible perialgal space. Chlorococcum reproduced in these vacuoles and up to eight daughter cells were found within the same vacuole. We suggest that the graded or scant distribution of chlorococci in the various brown hydra, their inability to live in H. viridis and the inability of the various chlorellae to live in brown hydra are the result of differences in nutrients available to the algae in the respective hosting cells. We conclude that host/symbiont specificity and the various forms of interrelations we show in green and brown hydra with chlorococci and chlorellae are based on nutritional-ecological factors. These interrelations demonstrate successive stages in the evolution of stable obligatoric symbioses from chance encounters of preadapted potential cosymbionts.

Sign in / Sign up

Export Citation Format

Share Document