The Discovery of the GSH Receptor in Hydra and Its Evolutionary Significance
Christopher A. Shaw in Glutathione in the Nervous System, 2018
The study of the activation of the feeding behavior of hydra by GSH provides the investigator with important advantages. First, the molecule GSH itself is sufficiently complex, though not too large, to allow one to make a significant number of analogs for determining the conformation(s) and structure–activity relationships of GSH necessary to activate the receptor. Second the very nature of the hydra itself simplifies matters for the experimenter: (i) the animal has a simple tissue-level structure; (ii) the receptor is on the surface of the outer epithelium; (iii) the biological response can be readily quantified; (iv) pure clones of the animals can be easily grown in the laboratory in kilogram quantities (wet weight); and (v) the fluid environment (medium) surrounding the receptor can be accurately controlled within a pH range of about 4–8 and over wide ranges of ion concentrations.
An Overview of Parasite Diversity
Eric S. Loker, Bruce V. Hofkin in Parasitology, 2015
Members of the kingdom Animalia (animals, or metazoans) are unique among the world’s organisms for the development in most of integrated nervous and muscular systems that give them unprecedented mobility and responsiveness to environmental circumstances. Animals are multicellular heterotrophs that usually acquire their energy from ingestion of organic compounds, although several parasitic groups acquire nutrients by absorption across their body walls. Many of the world’s most familiar and medically significant parasites are found among the animals. Parasitism has arisen independently on at least 60 occasions in animals, in both major and minor lineages. Some lineages of animals are exclusively parasitic, some have a mixture of free-living and parasitic species, and some as best we know are without parasitic representatives (Figure 2.16).
Norms and violations
Waltraud Ernst in Histories of the Normal and the Abnormal, 2006
Foucault proposes a grand model for human abnormality: the figure of the monster. Contained within this overarching figure are a number of subcategories of monstrosity, most notably in the present context that of King Louis XVI, from whom, Foucault argues, all human monsters are descended.20 The essence of the monster is that it combines categories in such a way that it does not conform to ‘the law’. From the Middle Ages to the eighteenth century the monster was something that transgressed the law of nature – a mixture of the human and the animal, for example. The modern monster, however, disturbs civil, canonical and religious law as well. It is defined more by aberrant behaviour than by irregular appearance. At the end of the eighteenth century, Foucault argues, the figure of ‘natural irregularity’ is overtaken by that of the moral monster, personified by the tyrannical, incestuous monarch, and memorably represented in the work of Sade.
CRISPR/Cas: from adaptive immune system in prokaryotes to therapeutic weapon against immune-related diseases
Published in International Reviews of Immunology, 2020
Juan Esteban Garcia-Robledo, María Claudia Barrera, Gabriel J. Tobón
All organisms are part of the three main branches of the tree of life, bacteria, archaea (prokaryotes), and eukaryotes, that split from a common Last Universal Common Ancestor (LUCA) [2, 15]. Multicellular eukaryotes comprising most of kingdom Animalia emerged approximately 600 million years ago during the metazoan age [16]. These metazoan organisms branched rapidly along different lineages, and about 500 million years ago multiple lineages emerged [16]. Even simple life forms such as prokaryotes and single-celled eukaryotes possess heritable innate immune mechanisms [17]. Alternatively, adaptive immune systems able to provide protection based on previous exposure to foreign invaders was thought to first appear with the rise of jawed vertebrates (a metazoan lineage) [16, 18]. The adaptive immune system is based on cellular and humoral components (T cells and B lymphocytes, respectively) expressing antigen-recognizing receptors. These receptors are formed by genetic recombination during cell fate determination and maturation, allowing for the creation of multiple cell clones expressing receptors specific for different epitopes of microorganisms [18, 19].
Antinociceptive peptides from venomous arthropods
Published in Toxin Reviews, 2023
Jessica A. I. Muller, Lai Y. Chan, Monica C. Toffoli-Kadri, Marcia R. Mortari, David J. Craik, Johannes Koehbach
Hymenoptera is an order that belongs to the class of insects. Well-known examples of animals of this order are ants, bees and wasps. Although they represent one of the largest order of insects in terms of individual species, they are little studied and to date, the only published structure of an antinociceptive peptide from Hymenoptera is the major component of bee venom, melittin (Duffy et al.2020). This peptide lacks cysteines in the sequence and is unstructured in water. In 30% 2,2,2-trifluoroethanol (TFE) it was shown to adopt an α-helical structure (Ramirez et al.2018) (Figure 3(F)). These characteristics are also observed with other small peptides from bees and wasps as well as many antimicrobial peptides (Yeaman and Yount 2003), allowing speculations that the other antinociceptive peptides isolated from this group may adopt a similar structure or similar short and helical peptides may have antinociceptive activity. Albeit their potential antinociceptive activity, due to their linear nature and lack of disulfide bonds these peptides are likely to have low stability. To date, only three analgesics peptides have been described with no reported studies from ants thus far (Table 1).
Historical development of the statistical classification of causes of death and diseases
Published in Cogent Medicine, 2021
Musaed Ali Alharbi, Godfrey Isouard, Barry Tolchard
In the eighteenth century, the Swede Carolus Linnaeus (famed for his botanical taxonomy) also classified the animal and mineral kingdoms, and attempted the same for diseases. His contemporaries (physicians) who focused on disease included F. Boissier de la Croix de Sauvages, Jean-Louis Marc Alibert and Erasmus Darwin (Moriyama et al., 2011; Pearn, 2011; Poynter, 1973). In his treatise Nosology Methodica, Sauvages applied similar principles to Linnaeus’ taxa, or units, applicable to all levels from kingdom to subspecies. He developed 10 classes, systematically subdivided into some 300 orders, according to medical symptoms (Poppensiek & Budd, 1966). William Cullen’s synopsis Nosologae Methodicae was published in 1775, followed in 1817 by John Mason Good’s A Physiological System of Nosology, which played an important role in the development of disease nomenclature. These scholars implemented pragmatic changes, instigating a morphological classification system that supported a pathology based on anatomical structure, and facilitating an understanding of epidemic diseases (Moriyama et al., 2011). As Thompson (2003) notes, historically, nomenclature and classification reflect the scientifically observed model that has developed parallel to the discipline.
Related Knowledge Centers
- Eukaryote
- Heterotroph
- Multicellular Organism
- Sexual Reproduction
- Kingdom
- Muscle Cell
- Motility
- Blastulation
- Animal Embryonic Development
- Species