Stress tolerance alteration in the freshwater cnidarian green hydra (Hydra viridissima) via symbiotic algae mutagenesis

Symbiosis ◽  
2020 ◽  
Vol 82 (3) ◽  
pp. 189-199
Author(s):  
Siao Ye ◽  
Meenakshi Bhattacharjee ◽  
Evan Siemann
Keyword(s):  
Stress Tolerance ◽  
Symbiotic Algae ◽  
Green Hydra

The green hydra symbiosis. VII. Conservation of the host cell habitat by the symbiotic algae

1982 ◽  
Vol 216 (1205) ◽  
pp. 415-426 ◽  
Keyword(s):  
Host Cell ◽  
Lysosomal Degradation ◽  
Normal Complement ◽  
Calcofluor White ◽  
Digestive Cells ◽  
Symbiotic Algae ◽  
Green Hydra ◽  
Fluorescent Agent ◽  
Almost All ◽  
Cell Base

Freshly isolated ‘European’ algae phagocytosed by digestive cells of ‘European’ green hydra were distinguished from the pre-existing popu­lation of algae by prestaining with the fluorescent agent Calcofluor White. Only a small number of phagocytosed ‘European’ algae or algae cultured from Paramecium bursaria avoided lysosomal degradation and were transported to the cell base in symbiotic digestive cells, although in aposymbionts up to 50% of phagocytosed algae were transported. Degradation of almost all phagocytosed algae also occurred in digestive cells of hydra containing only half the normal complement of algae, and in those of hydra symbiotic with algae cultured from Paramecium . The presence of algae at the bases of digestive cells appears to negate the mechanism by which potentially symbiotic algae normally avoid lysosomal attack. This protects the host cell and its symbionts from invasion by ‘foreign’ algae and suggests that once established the green hydra symbiosis is conservative in nature.

The green hydra symbiosis. IV. Entry of symbionts into digestive cells

1982 ◽  
Vol 216 (1202) ◽  
pp. 1-6 ◽  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Plasma Membrane ◽  
Digestive Cell ◽  
Particle Type ◽  
Digestive Cells ◽  
Symbiotic Algae ◽  
Green Hydra ◽  
Different Types ◽  
Scanning Electron

Scanning electron microscopy showed that particles, including symbiotic algae, non-symbiotic algae and latex spheres, entered digestive cells of European green hydra by two different types of phagocytosis: (i) they sank into crater-like formations of the digestive-cell surface; or (ii) they were enveloped by raised, funnel-like extensions of plasma membrane. The morphology selected did not depend on particle type: there was no evidence for specific recognition of symbiotic algae during phagocytosis.

scholarly journals Expulsion of Symbiotic Algae during Feeding by the Green Hydra – a Mechanism for Regulating Symbiont Density?

PLoS ONE ◽  
2008 ◽  
Vol 3 (7) ◽  
pp. e2603 ◽  
Author(s):  
Yelena Fishman ◽  
Eliahu Zlotkin ◽  
Daniel Sher
Keyword(s):  
Symbiotic Algae ◽  
Green Hydra

Response of green hydra (Hydra viridissima) to variability and directional changes in food availability

Biologia ◽  
2015 ◽  
Vol 70 (10) ◽  
Author(s):  
Márta E. Rosa ◽  
Flóra Bradács ◽  
Jácint Tökölyi
Keyword(s):  
Environmental Change ◽  
Stress Tolerance ◽  
Food Availability ◽  
Environmental Changes ◽  
Control Group ◽  
Delayed Response ◽  
Natural Environments ◽  
Feeding Frequency ◽  
Green Hydra ◽  
Response To Environmental Change

AbstractNatural environments tend to be variable resulting in alternating periods of high and low food availability. Therefore, animals have to be able to accommodate to sudden environmental changes by adjusting their physiology and behaviour to new conditions. We investigated how simulated food variability affects life history traits (asexual reproduction and stress tolerance) and response to environmental change in laboratory experiments with green hydra (Hydra viridissima). We assigned hydra into four groups differing in feeding frequency (high or low) and food regularity (random or stable). After 21 days of accommodation, feeding frequency was changed (increased or decreased) in half of each group, the other half was kept as a control group. Hydra showed a delayed response to environmental change (increased or decreased feeding frequency). This delay in response was greater under an unpredictable feeding scheme. Animals on a random scheme had lower budding rates and lower stress tolerance. Follow-up experiments suggest that this might be due to receiving food on subsequent days, since we found that animals fed daily have lower budding rates than those fed on alternate days. We hypothesize that frequent feeding might cause high levels of oxidative/xenobiotic stress which could overwhelm the defence system of these animals.

scholarly journals Temporal relationships of host cell and algal mitosis in the green hydra symbiosis

1982 ◽  
Vol 58 (1) ◽  
pp. 423-431
Author(s):  
P.J. McAuley
Keyword(s):  
Cell Division ◽  
Host Cell ◽  
Digestive Cell ◽  
Digestive Cells ◽  
Symbiotic Algae ◽  
Green Hydra ◽  
Temporal Relationships ◽  
Dividing Cells ◽  
Cell Mitosis ◽  
Mitotic Cells

In fed hydra or excised regenerating peduncles there are increases in the mitotic indices of both digestive cells and the symbiotic algae that reside within them. Conversely, algal and digestive cell mitotic indices decrease in starved hydra. The temporal relationships of algal and host cell division differ in fed hydra and regenerating peduncles. After feeding, algal and digestive cell mitotic indices both reach a peak at about the same time; during regeneration, first the algae and then the digestive cells divide. Thus, mitotic digestive cells in regenerating peduncles contain more algae than those in gastric regions of fed hydra. However, in both cases mitotic digestive cells contain more algae than non-mitotic cells. The algae appear to be partitioned at random between daughter digestive cells at teleophase. It is suggested that the division of the symbiotic algae is closely related to that of the digestive cells in which they maintained. Mitosis of algae is stimulated by host cell mitosis, but in non-dividing cells algal mitosis is restricted. Possible mechanisms by which the host digestive cells could restrict algal division are discussed.

The cell cycle of symbiotic Chlorella. IV. DNA content of algae slowly increases during host starvation of green hydra

1986 ◽  
Vol 85 (1) ◽  
pp. 73-84
Author(s):  
P.J. McAuley ◽  
L. Muscatine
Keyword(s):  
Cell Size ◽  
Dna Content ◽  
Algal Cell ◽  
S Phase ◽  
Symbiotic Algae ◽  
Daughter Cells ◽  
Green Hydra ◽  
Significant Difference ◽  
Preceding Period ◽  
Chlorella Algae

The distribution of DNA content of symbiotic Chlorella algae freshly isolated from green hydra was compared with that of cultured Chlorella of the NC64A strain, using flow cytometry. In nonlogarithmic cultures of NC64A most cells had accumulated in G1 phase, while in logarithmic cultures a peak containing cells in S phase and mitosis could be distinguished from the larger G1 peak. However, symbiotic algae showed a single broad peak in which there was no clear distinction between G1 and S phase/mitosis. When hydra were starved for a prolonged period, inhibiting host cell and algal division, the DNA content of the symbiotic algae slowly increased, and the number of daughter cells produced after a single feeding increased with the length of the preceding period of starvation. This suggests that symbiotic algae are able to cycle slowly through S phase, but unless the host is fed they cannot traverse into mitosis and complete the cell division cycle. No significant difference in cell size was found between algae producing either four or eight daughter cells after 1-day- or 22-day-starved hydra were fed, suggesting that algal cell size did not determine the number of daughter cells produced. Instead, this may be dependent upon the length of time the cell had spent in S phase prior to receiving the, as yet unknown, stimulus to enter into mitosis.

scholarly journals METABOLIC RELATIONSHIPS BETWEEN GREEN HYDRA AND ITS SYMBIOTIC ALGAE

1977 ◽  
Vol 153 (1) ◽  
pp. 228-236 ◽  
Author(s):  
ROSEVELT L. PARDY ◽  
BRIAN N. WHITE
Keyword(s):  
Symbiotic Algae ◽  
Green Hydra

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.

Investigating stress tolerance as a predictor of multitasking performance

2009 ◽  
Author(s):  
Ted B. Kinney ◽  
Mei-Chuan Kung ◽  
Kathleen M. Meckley ◽  
Kristin M. Delgado
Keyword(s):  
Stress Tolerance
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