scholarly journals Ontogenetic niche specialisation of the spider crab Libinia ferreirae associated with the medusa Lychnorhiza lucerna

2021 ◽  
Author(s):  
Geslaine Rafaela Lemos Gonçalves ◽  
Milena Regina Wolf ◽  
Mariana Antunes ◽  
Felipe Wanderley Amorim ◽  
Maria Lucia Negreiros-Fransozo ◽  
...  
Keyword(s):  
Temporal Correlation ◽  
Food Resources ◽  
Spider Crab ◽  
Early Life Stages ◽  
Free Living ◽  
Larval Phase ◽  
Water Currents ◽  
Symbiotic Relationships ◽  
Sea Bottom ◽  
Living Adult

Abstract Symbiotic relationships in marine environments are not fixed and can change throughout the animal’s life. This study investigated the ontogeny of symbiosis of the spider crab Libinia ferreirae with the host medusa Lychnorhiza lucerna. We described the type of relationship, the temporal correlation among species and food habits. More than 50% of the sampled crabs were symbionts, most in early life stages. The highest number of crabs found in a single medusa was 11. Symbiosis was observed throughout most of the year but was more evident in warm periods. The crab has many benefits in this relationship with a medusa. One is the use of food resources captured by the medusa, primarily copepods. Since the crab steals the medusa's food, it is a kleptoparasitic relationship. There is a niche partition between symbiont and the free-living crabs as they occupy different habitats and use nonoverlapping food resources. Previous research reported that symbiosis first developed during the crab’s last larval phase (megalopa) when crab and medusa are in the same habitat. Observation of the crab's behaviour shows that symbiosis occurs when the crab can grab to the medusa when the host touches the sea bottom. The crab also took advantage of water currents, releasing itself from the substrate and then drifting towards the medusa. The symbiotic relationship that crabs have with the medusa provides then with a nursery, food resources, shelter, dispersion, and decreased competition with free-living adult crabs, all essential for the crab's survival.

Developmental regulation and morphological saltation in the heteromorph ammonite Nipponites

Paleobiology ◽  
1988 ◽  
Vol 14 (3) ◽  
pp. 272-286 ◽  
Author(s):  
Takashi Okamoto
Keyword(s):  
Developmental Regulation ◽  
Shell Growth ◽  
Growth Direction ◽  
Intermediate Form ◽  
Free Living ◽  
Neutral Buoyancy ◽  
Life Orientation ◽  
Sea Bottom ◽  
Mode Of Life ◽  
Lower Limits

Nipponites, a Late Cretaceous nostoceratid ammonite, shows a peculiar meandering shell growth in the middle-late stage. Assuming neutral buoyancy, and a constant aperture angle relative to the sea bottom, meandering growth of this ammonite was modeled by computer simulation. In this model, the meandering shell growth is controlled by regulation of life orientation. The remarkable similarity in the coiling modes and rib obliquity patterns between the computer-simulated and actual specimens strongly suggests a free living mode of life in Nipponites with an approximately neutral buoyancy. The simulation also suggests that morphological saltation from a simple helicoid form like Eubostrychoceras japonicum to a meandering shell form like Nipponites occurred abruptly without any intermediate form by minor change of the upper and lower limits of growth direction.

scholarly journals A Sulfoglycolytic Entner-Doudoroff Pathway in Rhizobium leguminosarum bv. trifolii SRDI565

2020 ◽  
Vol 86 (15) ◽  
Author(s):  
Jinling Li ◽  
Ruwan Epa ◽  
Nichollas E. Scott ◽  
Dominik Skoneczny ◽  
Mahima Sharma ◽  
...  
Keyword(s):  
Rhizobium Leguminosarum ◽  
Glycolytic Enzyme ◽  
Proteomics Data ◽  
Free Living ◽  
Content Type ◽  
Biochemical Processes ◽  
Symbiotic Relationships ◽  
Rhizobium Isolate ◽  
Rhizobial Isolate ◽  
Metabolomics Analysis

ABSTRACT Rhizobia are nitrogen-fixing bacteria that engage in symbiotic relationships with plant hosts but can also persist as free-living bacteria in the soil and rhizosphere. Here, we show that free-living Rhizobium leguminosarum SRDI565 can grow on the sulfosugar sulfoquinovose (SQ) or the related glycoside SQ-glycerol using a sulfoglycolytic Entner-Doudoroff (sulfo-ED) pathway, resulting in production of sulfolactate (SL) as the major metabolic end product. Comparative proteomics supports the involvement of a sulfo-ED operon encoding an ABC transporter, sulfo-ED enzymes, and an SL exporter. Consistent with an oligotrophic lifestyle, proteomics data revealed little change in expression of the sulfo-ED proteins during growth on SQ versus mannitol, a result confirmed through biochemical assay of sulfoquinovosidase activity in cell lysates. Metabolomics analysis showed that growth on SQ involves gluconeogenesis to satisfy metabolic requirements for glucose-6-phosphate and fructose-6-phosphate. Metabolomics analysis also revealed the unexpected production of small amounts of sulfofructose and 2,3-dihydroxypropanesulfonate, which are proposed to arise from promiscuous activities of the glycolytic enzyme phosphoglucose isomerase and a nonspecific aldehyde reductase, respectively. The discovery of a rhizobium isolate with the ability to degrade SQ builds our knowledge of how these important symbiotic bacteria persist within soil. IMPORTANCE Sulfonate sulfur is a major form of organic sulfur in soils but requires biomineralization before it can be utilized by plants. Very little is known about the biochemical processes used to mobilize sulfonate sulfur. We show that a rhizobial isolate from soil, Rhizobium leguminosarum SRDI565, possesses the ability to degrade the abundant phototroph-derived carbohydrate sulfonate SQ through a sulfoglycolytic Entner-Doudoroff pathway. Proteomics and metabolomics demonstrated the utilization of this pathway during growth on SQ and provided evidence for gluconeogenesis. Unexpectedly, off-cycle sulfoglycolytic species were also detected, pointing to the complexity of metabolic processes within cells under conditions of sulfoglycolysis. Thus, rhizobial metabolism of the abundant sulfosugar SQ may contribute to persistence of the bacteria in the soil and to mobilization of sulfur in the pedosphere.

scholarly journals The life histories and population dynamics of monogenean gill parasites of Trachurus trachurus (L.)

1962 ◽  
Vol 42 (3) ◽  
pp. 587-600 ◽  
Author(s):  
J. Llewellyn
Keyword(s):  
Coastal Waters ◽  
Life Histories ◽  
Feeding Habits ◽  
Limiting Factor ◽  
Trachurus Trachurus ◽  
Free Living ◽  
Sea Bottom ◽  
Second Year ◽  
Post Spawning ◽  
Gill Parasites

Gastrocotyle trachuri and Pseudaxine trachuri infect young Trachurus trachurus at Plymouth as soon as the 3- or 4-month-old adolescent fishes descend to the sea bottom in October. The parasites normally mature in 3 or 4 months, but, exceptionally, in about 1 month, and the life-span is normally no longer than 1 year. Trachurus specimens at the beginning of their second year pick up a largely new infection of parasites.G. trachuri and P. trachuri are much less frequent on 2- and 3-year-old specimens of Trachurus and probably occur only very rarely on still older fishes, the limiting factor being not an age-immunity but a post-spawning migration of the host from the concentration of free-living infective stages of the parasites in coastal waters.The parasites have adapted themselves to a seasonal change in the feeding habits of Trachurus by ceasing to produce larvae in anticipation of the summer disappearance of scad from the sea bottom in pursuit of pelagic food-organisms.

Dietary Fiber and Lifestyle Influence Serum Lipids in Free Living Adult Men

2001 ◽  
Vol 20 (6) ◽  
pp. 649-655 ◽  
Author(s):  
Martha N. Ballesteros ◽  
Rosa M. Cabrera ◽  
Maria S. Saucedo ◽  
Gloria M. Yepiz-Plascencia ◽  
M. Isabel Ortega ◽  
...  
Keyword(s):  
Dietary Fiber ◽  
Serum Lipids ◽  
Free Living ◽  
Adult Men ◽  
Living Adult

The effect of non-immune stresses on the development of Strongyloides ratti

Parasitology ◽  
2005 ◽  
Vol 131 (3) ◽  
pp. 383-392 ◽  
Author(s):  
M. CROOK ◽  
M. E. VINEY
Keyword(s):  
Immune Response ◽  
Parasitic Nematode ◽  
Host Immune Response ◽  
Natural Host ◽  
Adult Males ◽  
Free Living ◽  
Developmental Effects ◽  
Adult Females ◽  
Males And Females ◽  
Living Adult

Strongyloides ratti is a parasitic nematode of rats. The host immune response against S. ratti affects the development of its free-living generation, favouring the development of free-living adult males and females at the expense of directly developing, infective 3rd-stage larvae. However, how the host immune response brings about these developmental effects is not clear. To begin to investigate this, we have determined the effect of non-immune stresses on the development of S. ratti. These non-immune stresses were subcurative doses of the anthelmintic drugs Ivermectin, Dithiazanine iodide and Thiabendazole, and infection of a non-natural host, the mouse. These treatments produced the opposite developmental outcome to that of the host immune response. Thus, in infections treated with subcurative doses of Ivermectin, Dithiazanine iodide and in infections of a non-natural host, the sex ratio of developing larvae became more female-biased and the proportion of female larvae that developed into free-living adult females decreased. This suggests that the mechanism by which the host immune response and these non-immune stresses affect S. ratti development differs.

scholarly journals Lychnorhiza lucerna Haeckel (Scyphozoa, Rhizostomeae) and Libinia ferreirae Brito Capello (Decapoda, Majidae) association in southern Brazil

2005 ◽  
Vol 22 (4) ◽  
pp. 908-912 ◽  
Author(s):  
Miodeli Nogueira Júnior ◽  
Maria A. Haddad
Keyword(s):  
The State ◽  
Ocean Bottom ◽  
Spider Crab ◽  
Southern Brazil ◽  
Free Living ◽  
Adult Crab

Associations between jellyfish and other organisms are frequently reported. Neverhteless, few of those records include crabs inhabiting medusae. Lychnorhiza lucerna Haeckel, 1888 were sampled (n = 1988) on the coast of the State of Paraná (25º20'-25º55'S, 48º10'-48º35'W), southern Brazil, from December 1997 to December 2004. Eight percent (166 individuals) of the medusae had one spider crab Libinia ferreirae Brito Capello, 1871 living within its subgenital porticus or on the oral arms. Megalopal stages of the same crab were also found on three jellyfish. All crabs associated with L. lucerna were young and smaller (< 3 cm) than solitary crabs caught on the bottom. Thus, L. ferreirae probably colonizes the jellyfish as a late larva and uses it as a floating nursery before becoming free-living on the ocean bottom as a typical adult crab.

scholarly journals Evaluation of a digital method to assess evening meal intake in a free-living adult population

2010 ◽  
Vol 54 (1) ◽  
pp. 5311 ◽  
Author(s):  
Anne Dahl Lassen ◽  
Sanne Poulsen ◽  
Lotte Ernst ◽  
Klaus Kaae Andersen ◽  
Anja Biltoft-Jensen ◽  
...  
Keyword(s):  
Adult Population ◽  
Digital Method ◽  
Evening Meal ◽  
Free Living ◽  
Meal Intake ◽  
Living Adult
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