scholarly journals Hypoxia increases the risk of egg predation in a nest-guarding fish

2016 ◽  
Vol 3 (8) ◽  
pp. 160326 ◽  
Author(s):  
Karin H. Olsson ◽  
Charlotta Kvarnemo ◽  
Maria Norevik Andrén ◽  
Therése Larsson
Keyword(s):  
Carcinus Maenas ◽  
High Oxygen ◽  
Filial Cannibalism ◽  
Defensive Behaviour ◽  
Low Oxygen ◽  
Pomatoschistus Minutus ◽  
Oxygen Treatment ◽  
Large Nest ◽  
Shore Crabs ◽  
Egg Guarding

For fish with parental care, a nest should meet both the oxygenation needs of the eggs and help protect them against predators. While a small nest opening facilitates the latter, it impedes the former and vice versa. We investigated how the presence of potential egg predators in the form of shore crabs Carcinus maenas affects nest building, egg fanning, defensive displays and filial cannibalism of egg-guarding male sand gobies Pomatoschistus minutus under two levels of dissolved oxygen. In the high oxygen treatment, males retained their nest opening size in the presence of crabs, while males in low oxygen built large nest openings both in the absence and presence of crabs, despite the fact that crabs were more likely to successfully intrude into nests with large entrances. Males in low oxygen also fanned more. In the presence of crabs males increased their defensive displays, but while males in high oxygen reduced fanning, males in low oxygen did not. Filial cannibalism was unaffected by treatment. Sand gobies thus prioritize egg ventilation over the protection afforded by small nest openings under hypoxia and adopt defensive behaviour to avert predator attention, even though this does not fully offset the threat from the egg predators.

scholarly journals Hurry-up and hatch: selective filial cannibalism of slower developing eggs

2008 ◽  
Vol 4 (2) ◽  
pp. 160-162 ◽  
Author(s):  
Hope Klug ◽  
Kai Lindström
Keyword(s):  
Egg Size ◽  
Adaptive Strategy ◽  
Filial Cannibalism ◽  
Sand Goby ◽  
Pomatoschistus Minutus ◽  
Fitness Consequences

Filial cannibalism (the consumption of one's own offspring) is thought to represent an adaptive strategy in many animals. However, little is known about the details of which offspring are consumed when a parent cannibalizes. Here, we examined patterns of within-brood filial cannibalism in the sand goby ( Pomatoschistus minutus ). Males spawned sequentially with two females, and we asked whether males cannibalized selectively with regard to egg size or the order in which eggs were received. Males preferentially consumed the larger eggs of the second female they spawned with. Because larger eggs took longer to hatch, and because female 2's eggs were up to 1 day behind those of female 1, such preferential cannibalism might allow males to decrease the time spent caring for the current brood and re-enter the mating pool sooner. More work is needed to understand the fitness consequences of such selective cannibalism.

scholarly journals Influence of temperature on intraspecific, unbalanced dyadic contests between crabs

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7845
Author(s):  
Allan T. Souza ◽  
Felipe O. Ribas ◽  
João F. Moura ◽  
Claudia Moreira ◽  
Joana Campos ◽  
...  
Keyword(s):  
Carapace Width ◽  
Carcinus Maenas ◽  
Individual Characteristics ◽  
The Body ◽  
Shore Crab ◽  
Temperature Conditions ◽  
Red Color ◽  
Shore Crabs ◽  
Influence Of Temperature On ◽  
Globally Distributed

Intraspecific agonistic interactions are widespread across the animal kingdom, with many individual morphological and physiological characteristics playing important roles in the fate of disputes. Additionally, changes to environmental conditions can influence the outcomes of animal contests. The shore crab (Carcinus maenas) is a globally distributed species, present in numerous coastal and estuarine temperate systems around the world. Although shore crabs are highly tolerant to changes in temperature, this parameter has important physiological effects on the species’ ecology, while its effects on behavior are not fully understood. Our study aims to investigate how different individual characteristics (such as sex, color morphotype, carapace and chela morphology) and temperature conditions affect the dyadic interactions between shore crabs when disputing food resources. In general, the differences in carapace width between opponents, their sexes, color morphotypes and the temperature conditions interacted and were important predictors of the contest fate. We found that the body size and color morphotype of C. maenas determined the fate of dyadic disputes. However, the higher temperatures disrupted the well-established dominance of the larger red color morphotype individuals. Overall, the agonistic contest results suggest higher plasticity than previously acknowledged.

Fine Temporal Mapping of Plasmodium Falciparum growth Inhibition in Hypoxic Sickle Cell Trait Erythrocytes

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 924-924
Author(s):  
Natasha Archer ◽  
Nicole Petersen ◽  
Martha Clark ◽  
Manoj Duraisingh
Keyword(s):  
Flow Cytometry ◽  
Carbon Monoxide ◽  
Dna Replication ◽  
Oxygen Tension ◽  
Sickle Cell ◽  
Sickle Cell Trait ◽  
High Oxygen ◽  
Low Oxygen ◽  
Trophozoite Stage ◽  
Sickle Hemoglobin

Abstract Background: Despite the global acceptance of Haldane's hypothesis that individuals with sickle cell trait (AS) are protected against malaria, an exact mechanism of resistance remains unknown. Several theories to explain the resistance such as increased splenic destruction, impaired hemoglobin digestion, reduced cytoadherence and specific translocation of host specific microRNAs have been proposed. Here we carefully examine the influence of hypoxia and its relation to parasite cytoadherence and growth in AS and normal (AA) human red blood cells (RBCs). Materials and Methods: To assess the influence of oxygen tension on parasite proliferation in AS RBCs, we followed the proliferation of tightly synchronized P. falciparum within AS and AA RBCs at 1, 5, 10, and 17% oxygen by flow cytometry and microscopy. Carbon monoxide (CO) studies were performed by introducing 100% CO gas into our enclosed chamber system every 21 hours to prevent sickling at low oxygen. Results: Flow cytometry assessment of DNA content confirms the absence of DNA replication within parasites in AS erythrocytes at low oxygen, however normal DNA replication is observed in the presence of high oxygen tension and when CO is introduced at low oxygen. Moving parasites from high to low oxygen tension greatly influences the extent of parasite maturity; parasites moved at 16 and 20 hours post invasion (hpi) do not mature beyond that of the late ring/early trophozoite stage while parasites moved at 24, 28, and 32 hpi develop increasingly more merozoites. Conclusion: Here, we show that in hypoxic conditions parasites in AS erythrocytes stall at the late ring/early trophozoite stage and do not replicate their DNA. We also show that treatment of AS erythrocytes with high oxygen tension or carbon monoxide, a potent inhibitor of sickle hemoglobin polymerization, reverses this phenotype. We propose that the mechanism of AS protection is largely due to P.falciparum's inability to digest polymerized sickle hemoglobin once the parasite sequesters in the hypoxic microvasculature. This is likely a key driver of the reduced parasite densities observed in actual infections in AS individuals. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

323 INTERACTIONS OF OXYGEN TENSION, GLUCOSE CONCENTRATION, AND HEAT SHOCK ON MATURATION OF BOVINE OOCYTES

2006 ◽  
Vol 18 (2) ◽  
pp. 269
Author(s):  
L. A. de Castro e Paula ◽  
P. J. Hansen
Keyword(s):  
Heat Shock ◽  
Oxygen Tension ◽  
High Glucose ◽  
Glucose Concentration ◽  
High Oxygen ◽  
High Glucose Concentration ◽  
Blastocyst Formation ◽  
Low Oxygen ◽  
Main Effects ◽  
Bovine Oocytes

In many cell types, oxygen tension and glucose concentration affect the magnitude of heat shock effects. Experiments were performed to (1) develop oocyte maturation protocols under high (20.95%) and low (5%) oxygen tensions, and (2) test the hypothesis that low oxygen tension and high glucose concentration reduce the magnitude of the deleterious effects of heat shock on in vitro maturation of bovine oocytes. In Experiment 1, oocytes were matured in tissue culture medium-199 (TCM-199) or synthetic oviduct fluid (SOF) containing 5.6 or 20 mM glucose, under either high or low oxygen. Fertilization was performed under high oxygen and embryos were cultured in KSOM-BE2 under low oxygen. Data were analyzed by least squares analysis of variance using the GLM procedure of SAS (SAS Institute, Inc., Cary, NC, USA), with maturation medium, glucose concentration, and oxygen tension as main effects. Oxygen concentration affected percent blastocyst formation when TCM-199 was used (greater for high oxygen than low oxygen) but not when SOF was used (medium � oxygen, P < 0.05). Similarly, glucose had no effect on percent blastocyst formation under high oxygen but high glucose was superior under low oxygen (glucose � oxygen, P < 0.05). Therefore, SOF with either 5.6 or 20 mM glucose was used to study the effect of heat shock on maturation under high and low oxygen in Experiment 2. Maturation was at 38.5�C for 22 h (control) or 41�C for 12 h and 38.5�C for 10 h (heat shock). Fertilization was performed at 38.5�C under high oxygen and embryos were cultured in KSOM-BE2 under low oxygen at 38.5�C. Data were analyzed as described above with glucose concentration, temperature and oxygen tension as main effects. The experiment was replicated nine times with a total of 3215 embryos. Heat shock decreased the cleavage rate slightly regardless of the maturation conditions (69 � 1% vs. 66 � 1%, P < 0.01). For oocytes matured in 5.6 mM glucose, percent blastocyst formation was greater for high oxygen while there was no effect of oxygen tension for oocytes matured in 20 mM glucose (glucose � oxygen, P < 0.01). Heat shock decreased the percent blastocyst formation under all maturation conditions except for the group matured under high oxygen and high glucose (temperature � oxygen � medium, P = 0.07; temperature � oxygen for oocytes under 5% oxygen; P < 0.05). The percent blastocyst formation for control and heat-shocked oocytes was 25.9% vs. 22.5% (low oxygen-5.6 mM glucose), 41.6% vs. 34.9% (low-20 mM), 41.7% vs. 35.0% (high-5.6 mM), and 37.6% vs. 37.5% (high-20 mM) (SEM = 2.0%). In conclusion, heat shock during maturation under an oxygen tension (5% oxygen) that approaches physiological conditions reduces the percent blastocyst formation. Moreover, a high glucose concentration protects oocytes from heat shock under high oxygen. This work was supported by USDA NRICGP 2002-35203-12664 and CAPES #134202-9.

scholarly journals Mycosis Is a Disease State Encountered Rarely in Shore Crabs, Carcinus maenas

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 462
Author(s):  
Charlotte E. Davies ◽  
Sophie H. Malkin ◽  
Jessica E. Thomas ◽  
Frederico M. Batista ◽  
Andrew F. Rowley ◽  
...  
Keyword(s):  
Immune Cell ◽  
Fungal Infections ◽  
Novel Species ◽  
Carcinus Maenas ◽  
Shore Crab ◽  
Marine Animals ◽  
Cell Reactivity ◽  
Shore Crabs ◽  
Swansea Bay ◽  
Disease Signatures

There is a paucity of knowledge regarding the diversity and impact(s) of disease-causing fungi in marine animals, especially shellfish. In efforts to address this knowledge gap for the shore crab Carcinus maenas, a year-long disease screen was carried out across two sites in Swansea Bay (Wales, UK) with a view to characterising putative fungal infections. Crabs were sampled between November 2017 and October 2018, and screened systematically for disease signatures using haemolymph (blood) preparations, targeted PCR and tissue histopathology. Strikingly, mycosis was confirmed in ~0.4% of total crabs tested (n = 1191) and restricted to one location only (Mumbles Pier). Clinical infections were observed in four out of four infected crabs. In these animals, the gills and hepatopancreas were congested with fungal morphotypes. In addition, some evidence indicates haemocyte (immune cell) reactivity toward the fungi. Phylogenetic placement of the partial internal transcribed spacer (ITS1) gene regions amplified from three mycotic crabs revealed the causative agent to be related to hypocrealean fungi, thereby representing a novel species.

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