Interference and Exploitation Competition Among Tadpoles of Rana Utricularia

Ecology ◽  
1978 ◽  
Vol 59 (5) ◽  
pp. 1039-1046 ◽  
Author(s):  
Kurt Steinwascher
Keyword(s):  
Exploitation Competition ◽  
Rana Utricularia

scholarly journals Mechanisms Involved in Interspecific Communication between Wine Yeasts

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1734
Author(s):  
Ana Mencher ◽  
Pilar Morales ◽  
Jordi Tronchoni ◽  
Ramon Gonzalez
Keyword(s):  
Alcoholic Fermentation ◽  
Yeast Species ◽  
Interspecific Interactions ◽  
Interference Competition ◽  
Weighted Average ◽  
Starter Cultures ◽  
Simple Consequence ◽  
Wine Yeasts ◽  
Exploitation Competition ◽  
Metabolic Intermediates

In parallel with the development of non-Saccharomyces starter cultures in oenology, a growing interest has developed around the interactions between the microorganisms involved in the transformation of grape must into wine. Nowadays, it is widely accepted that the outcome of a fermentation process involving two or more inoculated yeast species will be different from the weighted average of the corresponding individual cultures. Interspecific interactions between wine yeasts take place on several levels, including interference competition, exploitation competition, exchange of metabolic intermediates, and others. Some interactions could be a simple consequence of each yeast running its own metabolic programme in a context where metabolic intermediates and end products from other yeasts are present. However, there are clear indications, in some cases, of specific recognition between interacting yeasts. In this article we discuss the mechanisms that may be involved in the communication between wine yeasts during alcoholic fermentation.

scholarly journals Interference competition pressure predicts the number of avian predators that shifted their timing of activity

2018 ◽  
Vol 285 (1880) ◽  
pp. 20180744 ◽  
Author(s):  
Yifan Pei ◽  
Mihai Valcu ◽  
Bart Kempenaers
Keyword(s):  
Species Richness ◽  
Body Size ◽  
Interference Competition ◽  
Relative Importance ◽  
Exploitation Competition ◽  
Predator Species ◽  
Avian Predator ◽  
Avian Predators ◽  
Time Partitioning ◽  
Competition Pressure

Being active at different times facilitates the coexistence of functionally similar species. Hence, time partitioning might be induced by competition. However, the relative importance of direct interference and indirect exploitation competition on time partitioning remains unclear. The aim of this study was to investigate the relative importance of these two forms of competition on the occurrence of time-shifting among avian predator species. As a measure of interference competition pressure, we used the species richness of day-active avian predator species or of night-active avian predator species (i.e. species of Accipitriformes, Falconiformes and Strigiformes) in a particular geographical area (assemblage). As an estimate of exploitation competition pressure, we used the total species richness of avian predators in each assemblage. Estimates of the intensity of interference competition robustly predicted the number of Accipitriformes species that became crepuscular and the number of Strigiformes species that became day-active or strictly crepuscular. Interference competition pressure may depend on body size and on the total duration of the typical active period (day or night length). Our results support—to some extent—that smaller species are more likely to become time-shifters. Day length did not have an effect on the number of time-shifter species in the Accipitriformes. Among the large Strigiformes, more time-shifter species occur in areas where nights are shorter (i.e. where less of the typical time resource is available). However, in the small Strigiformes, we found the opposite, counterintuitive effect: more time-shifters where nights are longer. Exploitation competition may have had an additional positive effect on the number of time-shifters, but only in Accipitriformes, and the effect was not as robust. Our results thus support the interference competition hypothesis, suggesting that animals may have shifted their time of activity, despite phylogenetic constraints on the ability to do so, to reduce the costs of direct interactions. Our findings also highlight the influence of body size as a surrogate of competitive ability during encounters on time partitioning, at least among avian predators.

scholarly journals Competition among Nasal Bacteria Suggests a Role for Siderophore-Mediated Interactions in Shaping the Human Nasal Microbiota

2018 ◽  
Vol 85 (10) ◽  
Author(s):  
Reed M. Stubbendieck ◽  
Daniel S. May ◽  
Marc G. Chevrette ◽  
Mia I. Temkin ◽  
Evelyn Wendt-Pienkowski ◽  
...  
Keyword(s):  
Nasal Cavity ◽  
Iron Acquisition ◽  
Interference Competition ◽  
Human Microbiome ◽  
Human Microbiome Project ◽  
Siderophore Production ◽  
Coagulase Negative Staphylococci ◽  
Exploitation Competition ◽  
Content Type

ABSTRACTResources available in the human nasal cavity are limited. Therefore, to successfully colonize the nasal cavity, bacteria must compete for scarce nutrients. Competition may occur directly through interference (e.g., antibiotics) or indirectly by nutrient sequestration. To investigate the nature of nasal bacterial competition, we performed coculture inhibition assays between nasalActinobacteriaandStaphylococcusspp. We found that isolates of coagulase-negative staphylococci (CoNS) were sensitive to growth inhibition byActinobacteriabut thatStaphylococcus aureusisolates were resistant to inhibition. AmongActinobacteria, we observed thatCorynebacteriumspp. were variable in their ability to inhibit CoNS. We sequenced the genomes of 10Corynebacteriumspecies isolates, including 3Corynebacterium propinquumisolates that strongly inhibited CoNS and 7 otherCorynebacteriumspecies isolates that only weakly inhibited CoNS. Using a comparative genomics approach, we found that theC. propinquumgenomes were enriched in genes for iron acquisition and harbored a biosynthetic gene cluster (BGC) for siderophore production, absent in the noninhibitoryCorynebacteriumspecies genomes. Using a chrome azurol S assay, we confirmed thatC. propinquumproduced siderophores. We demonstrated that iron supplementation rescued CoNS from inhibition byC. propinquum, suggesting that inhibition was due to iron restriction through siderophore production. Through comparative metabolomics and molecular networking, we identified the siderophore produced byC. propinquumas dehydroxynocardamine. Finally, we confirmed that the dehydroxynocardamine BGC is expressedin vivoby analyzing human nasal metatranscriptomes from the NIH Human Microbiome Project. Together, our results suggest that bacteria produce siderophores to compete for limited available iron in the nasal cavity and improve their fitness.IMPORTANCEWithin the nasal cavity, interference competition through antimicrobial production is prevalent. For instance, nasalStaphylococcusspecies strains can inhibit the growth of other bacteria through the production of nonribosomal peptides and ribosomally synthesized and posttranslationally modified peptides. In contrast, bacteria engaging in exploitation competition modify the external environment to prevent competitors from growing, usually by hindering access to or depleting essential nutrients. As the nasal cavity is a nutrient-limited environment, we hypothesized that exploitation competition occurs in this system. We determined thatCorynebacterium propinquumproduces an iron-chelating siderophore, and this iron-sequestering molecule correlates with the ability to inhibit the growth of coagulase-negative staphylococci. Furthermore, we found that the genes required for siderophore production are expressedin vivo. Thus, although siderophore production by bacteria is often considered a virulence trait, our work indicates that bacteria may produce siderophores to compete for limited iron in the human nasal cavity.

scholarly journals Grazers and Diggers: Exploitation Competition and Coexistence among Foragers with Different Feeding Strategies on a Single Resource

2000 ◽  
Vol 155 (2) ◽  
pp. 266-279 ◽  
Author(s):  
Shane A. Richards ◽  
Roger M. Nisbet ◽  
William G. Wilson ◽  
Hugh P. Possingham
Keyword(s):  
Feeding Strategies ◽  
Exploitation Competition

Exploitation Competition

2016 ◽  
Author(s):  
Monica Nordberg ◽  
Douglas M. Templeton ◽  
Ole Andersen ◽  
John H. Duffus
Keyword(s):  
Exploitation Competition

scholarly journals Structural analysis of a new series of oligosaccharide-alditols released by reductive β-elimination from oviducal mucins of Rana utricularia

1998 ◽  
Vol 330 (1) ◽  
pp. 469-478 ◽  
Author(s):  
Willy MORELLE ◽  
Gérard STRECKER
Keyword(s):  
Gel Permeation Chromatography ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Amphibian Species ◽  
Structural Investigations ◽  
Jelly Coat ◽  
Specific Material ◽  
Species Specific ◽  
Carbohydrate Chains ◽  
Rana Utricularia

Egg jelly coats from Rana utricularia are formed by components secreted along the oviduct. These secretion products overlay the oocytes as they pass along the different oviducal portions. In this study, carbohydrate chains of the jelly coat surrounding the eggs of R. utricularia were released by alkali/borohydride treatment. Fractionation of O-linked oligosaccharide-alditols was achieved by a combination of chromatographic techniques comprising anion-exchange chromatography, gel-permeation chromatography and HPLC on a silica column bonded with aminopropyl groups. Structural characterization was performed by one- and two-dimensional 1H-NMR spectroscopy in combination with matrix-assisted laser-desorption ionization-time of flight MS and methylation analysis. Ten oligosaccharide structures possessing a core consisting of Galβ(1 → 3)GalNAc-ol with or without branching through a GlcNAc residue linked β(1 → 6) to the GalNAc residue (core type 2 or core type 1 respectively) are described. The most representative carbohydrate sequences are: GlcNAc(β1-3)[Fuc(α1-4)]GlcNAc, GalNAc(α1-3)[Fuc(α1-2)]Gal(β1-4)GlcNAc(β1-3)GlcNAc and Gal(β1-3)GlcNAc(α1-3)[Fuc(α1-2)]Gal(β1-4)GlcNAc. The carbohydrate chains isolated from R. utricularia are quite different from those found in other amphibian species, in which the presence of species-specific material has been characterized. Since the jellies surrounding amphibian eggs are involved in egg-sperm interactions, these structural investigations can provide biochemical support for investigation of the fertilization process.

Sign in / Sign up

Export Citation Format

Share Document