scholarly journals Chemotaxis and chemical defenses in seaweed susceptibility to herbivory

2000 ◽  
Vol 60 (3) ◽  
pp. 405-414 ◽  
Author(s):  
R. C. PEREIRA ◽  
R. DONATO ◽  
V. L. TEIXEIRA ◽  
D. N. CAVALCANTI
Keyword(s):  
Chemical Defense ◽  
Brown Alga ◽  
Sea Urchins ◽  
Feeding Preference ◽  
Chemical Defenses ◽  
Feeding Deterrent ◽  
Limited Mobility ◽  
Dictyota Menstrualis ◽  
Close Relationship ◽  
Herbivore Species

Recent studies have show that small marine herbivores with limited mobility (mesograzers) often feed on macroalgae chemically defended against fishes or sea-urchins. In order to verify the involved mechanisms of chemotaxis or chemical defense into this process in Brazilian littoral, two species of brown alga Dictyota menstrualis and Dictyota mertensii were studied against the limited mobility herbivores, the amphipod Parhyale hawaiensis and the crab Pachygrapsus transversus. These two species were studied in order to verify the action of their crude extracts in the defense and chemotaxis processes related to limited mobility of these herbivores. Feeding preference assays revealed that P. hawaiensis do not eaten these Dictyota species. P. transversus do not eaten D. menstrualis either, but consumed large amounts of D. mertensii. Chemical deterrence assays showed that extracts of these species act as feeding deterrent to both species of herbivores. In addition, chemotaxis assays demonstrated that both herbivores are significantly negative chemotactic probably due to the presence of complementary metabolites into artificial foods. Considering that both Dictyota species exhibit active extracts against these small herbivores, we suppose that the non-occurrence of these herbivore species in close relationship with the seaweeds D. menstrualis and D. mertensii may explain the defense action of both extracts related to these mesograzers.

A dolabellane diterpene from the brown alga Dictyota pfaffii as chemical defense against herbivores

2004 ◽  
Vol 47 (2) ◽  
Author(s):  
Jussara P. Barbosa ◽  
Valéria L. Teixeira ◽  
Renato C. Pereira
Keyword(s):  
Chemical Defense ◽  
Brown Alga

Structures of secospatane-type diterpenes with feeding-deterrent activity from the brown alga

1989 ◽  
Vol 30 (12) ◽  
pp. 1567-1570 ◽  
Author(s):  
Kazuya Kurata ◽  
Kazuya Taniguchi ◽  
Kazunari Shiraishi ◽  
Minoru Suzuki
Keyword(s):  
Brown Alga ◽  
Feeding Deterrent ◽  
Deterrent Activity

scholarly journals A review of chemical defense in harlequin toads (Bufonidae; Atelopus)

2021 ◽  
Author(s):  
Kannon Pearson ◽  
Rebecca Tarvin
Keyword(s):  
Chemical Defense ◽  
Small Molecule ◽  
Chemical Defenses ◽  
Evolutionary Perspective ◽  
Unique Combination ◽  
Selective Pressures ◽  
Environmental Toxin ◽  
Biological Sources ◽  
Biochemical Research ◽  
Existing Data

Toads of the genus Atelopus are chemically defended by a unique combination of endogenously synthesized cardiotoxins (bufadienolides) and what are likely exogenously sequestered neurotoxins (guanidinium alkaloids). Investigation into Atelopus small-molecule chemical defenses has been primarily concerned with identifying and characterizing various forms of these toxins while largely overlooking their ecological roles and evolutionary implications. In addition to describing the extent of knowledge about Atelopus toxin structures, pharmacology, and biological sources, we review the detection, identification, and quantification methods used in studies of Atelopus toxins to date and conclude that many known toxin profiles are unlikely to be comprehensive because of methodological and sampling limitations. Patterns in existing data suggest that both environmental (toxin availability) and genetic (capacity to synthesize or sequester toxins) factors influence toxin profiles. From an ecological and evolutionary perspective, we summarize the possible selective pressures acting on Atelopus toxicity and toxin profiles, including predation, intraspecies communication, disease, and reproductive status. Ultimately, we intend to provide a basis for future ecological, evolutionary, and biochemical research on Atelopus.

scholarly journals Feeding Deterrent Effect of the Methanol Extract from the Brown Alga Dilophus okamurai against the Sea Urchin Stronglyocentrotus nudus.

1991 ◽  
Vol 57 (8) ◽  
pp. 1591-1595 ◽  
Author(s):  
Kazunari Shiraishi ◽  
Kazuya Taniguchi ◽  
Kazuya Kurata ◽  
Minoru Suzuki
Keyword(s):  
Sea Urchin ◽  
Brown Alga ◽  
Methanol Extract ◽  
Feeding Deterrent ◽  
Deterrent Effect

scholarly journals Chemical defense of Hymeniacidon heliophila (Porifera: halichondrida) against tropical predators

2010 ◽  
Vol 58 (4) ◽  
pp. 315-321 ◽  
Author(s):  
Suzi Meneses Ribeiro ◽  
Éverson Miguel Bianco ◽  
Ricardo Rogers ◽  
Valéria Laneuville Teixeira ◽  
Renato Crespo Pereira
Keyword(s):  
Secondary Metabolites ◽  
Fish Consumption ◽  
Sea Urchins ◽  
Chemical Compounds ◽  
Chemical Defenses ◽  
Hermit Crabs ◽  
Lytechinus Variegatus ◽  
Benthic Organisms ◽  
Different Types ◽  
Ecological Roles

Various benthic organisms have chemical defenses which reduce their predators' consumption. Although their efficiency may be noticed in many organisms, many of their effects are not well- known yet. Multiple ecological roles of secondary metabolites are shown in some sponges, which may represent an adaptative advantage considering the high amount of energy used to produce these chemical compounds. The goal of this work was to investigate the defensive property of the extracts from the sponge Hymeniacidon heliophila against the tropical predators: hermit crabs (Calcinus tibicens), sea urchins (Lytechinus variegatus) and generalist fishes. Extracts obtained with n-hexane, ethyl acetate and acetone/methanol were used in assays and all of them were effective in reducing the consumption by C. tibicens; n-hexane extract reduced the consumption by L. variegatus; and medium polarity extracts reduced fish consumption. Either the variation in action or the multiple ecological roles of the extracts indicates that different types of compounds can be associated to the defensive system produced by H. heliophila.

Life history of Bursaphelenchus conicaudatus (Nematoda: Aphelenchoididae) in relation to the yellow-spotted longicorn beetle, Psacothea hilaris (Coleoptera: Cerambycidae)

Nematology ◽  
2001 ◽  
Vol 3 (5) ◽  
pp. 473-479 ◽  
Author(s):  
Natsumi Kanzaki ◽  
Kazuyoshi Futai
Keyword(s):  
Life History ◽  
Pine Wilt Disease ◽  
Nematode Species ◽  
Feeding Preference ◽  
Life Cycles ◽  
Pinewood Nematode ◽  
Dispersal Pattern ◽  
Longicorn Beetle ◽  
Close Relationship ◽  
History Of

AbstractThe life history of the nematode Bursaphelenchus conicaudatus and its phoretic relationship to the yellow-spotted longicorn beetle, Psacothea hilaris, were studied, and are discussed by comparison with those of the pinewood nematode B. xylophilus, the pathogen of the pine wilt disease, and its vectors Monochamus species. The life history of B. conicaudatus was found to be very similar to that of B. xylophilus in dispersal pattern, vector selection and feeding preference, although the average number of B. conicaudatus carried by the yellow-spotted longicorn beetle, the proportion of beetles infested with the nematodes, and the nematode release pattern differed from those of B. xylophilus. These findings indicate a close relationship between the two species of Bursaphelenchus and the cerambycid beetles, as well as the adaptability of these two nematode species to the life cycles of their vectors.

scholarly journals Chemical Defense Mechanisms and Ecological Implications of Indo-Pacific Holothurians

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4808
Author(s):  
Elham Kamyab ◽  
Sven Rohde ◽  
Matthias Y. Kellermann ◽  
Peter J. Schupp
Keyword(s):  
Chemical Defense ◽  
Defense Mechanisms ◽  
Sea Cucumber ◽  
Pathogenic Bacteria ◽  
Ecological Factors ◽  
Chemical Defenses ◽  
Sea Cucumbers ◽  
Defense Compounds ◽  
Crude Extracts ◽  
Pharmacologically Active

Sea cucumbers are slow-moving organisms that use morphological, but also a diverse combination of chemical defenses to improve their overall fitness and chances of survival. Since chemical defense compounds are also of great pharmaceutical interest, we pinpoint the importance of biological screenings that are a relatively fast, informative and inexpensive way to identify the most bioactive organisms prior to further costly and elaborate pharmacological screenings. In this study, we investigated the presence and absence of chemical defenses of 14 different sea cucumber species from three families (Holothuriidae, Stichopodidae and Synaptidae) against ecological factors such as predation and pathogenic attacks. We used the different sea cucumber crude extracts as well as purified fractions and pure saponin compounds in a portfolio of ecological activity tests including fish feeding assays, cytotoxicity tests and antimicrobial assays against environmental pathogenic and non-pathogenic bacteria. Furthermore, we quantified and correlated the concentrations of sea cucumber characteristic saponin compounds as effective chemical defensive compounds in all 14 crude extracts by using the vanillin–sulfuric acid test. The initial results revealed that among all tested sea cucumber species that were defended against at least one ecological threat (predation and/or bacterial attack), Bohadschiaargus, Stichopuscholoronotus and Holothuria fuscopunctata were the three most promising bioactive sea cucumber species. Therefore, following further fractionation and purification attempts, we also tested saponin-containing butanol fractions of the latter, as well as two purified saponin species from B. argus. We could demonstrate that both, the amount of saponin compounds and their structure likely play a significant role in the chemical defense strategy of the sea cucumbers. Our study concludes that the chemical and morphological defense mechanisms (and combinations thereof) differ among the ecological strategies of the investigated holothurian species in order to increase their general fitness and level of survival. Finally, our observations and experiments on the chemical ecology of marine organisms can not only lead to a better understanding of their ecology and environmental roles but also can help in the better selection of bioactive organisms/compounds for the discovery of novel, pharmacologically active secondary metabolites in the near future.

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