Search results for " Structures"
showing 10 items of 4162 documents
Neuronal and neuroendocrine mechanisms of social rank and stress coping in teleost fish
2015
Fights for social dominance are stressful and results in an activation of the brain serotonergic system. Subordinate animals in an established dominance hierarchy are characterized by a chronic elevation of brain serotonergic activity, an effect that seems to mediate the behavioural inhibition observed in these animals. By contrast, social dominance has been associated with elevated dopaminergic activity, and dopamine (DA) has behavioural effects to some extent opposing those of serotonin (5HT). In addition to effects of the social environment, brain monoaminergic functions are controlled by genetic factors. For instance, zebrafish (Danio rerio) classified as bold, showing a propensity for …
The Effect of Cantharellus Cibarius Addition on Quality Characteristics of Frankfurter during Refrigerated Storage
2019
The antioxidant and antimicrobial properties of Cantharellus cibarius decoction and the effect of mushroom addition on the physicochemical and microbiological properties of frankfurters during refrigerated storage were studied. Mushroom addition significantly reduced (p <
External and internal elimination of supernumerary larvae in the whitefly parasitoid Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae)
2008
Abstract The solitary parasitoid Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) is one of the key biological control agents of the whitefly Bemisia argentifolii Bellows & Perring, also known as B. tabaci (Gennadius) B-biotype (Homoptera: Aleyrodidae). We present new information on its biology, and particularly about larval elimination during the first instar in cases of superparasitism. For the first time, physical elimination of supernumerary larvae was observed, both outside and inside the host. These findings are documented with confocal microscopy images and video recordings. We observed more than 350 B. argentifolii nymphs, parasitized with one, two or more than two larvae. Physi…
Molecular mechanisms in developmental biology.
1996
Some general molecular mechanisms underlying development are described. Namely: those involved in the differentiation of the R7 receptor in Drosophila embryonic retina; those involved in the determination of embryonic axes and in polar cell differentiation, in Drosophila; those involved in the determination of the AB and P cell lineage and in vulva differentiation in Caenorhabditis embryos.
Testing Acute Toxicity in the Embryo of Zebrafish, Brachydanio rerio, as an Alternative to the Acute Fish Test: Preliminary Results
1994
Acute toxicity testing in fish is a standard method used in estimating the influences of chemicals on aquatic vertebrates. The ecotoxicological data obtained from acute toxicity tests in fish are, however, not sufficiently reliable to justify the continued use of this test. Fertilised eggs of zebrafish ( Brachydanio rerio) were used to test the acute toxicity of chemicals. They were chosen because the development of B. rerio has been studied extensively and information already exists concerning the normal development of this species. The following parameters of the development of B. rerio were observed: coagulation of the egg, gastrulation, number of somites, movement, development of organ…
Corrigendum to “Imaging of nitric oxide in a living vertebrate using a diaminofluorescein probe” [Free Radic. Biol. Med. 43 (2007) 619–627]
2008
Adrian Grimes and colleagues showed in a previous report that zebrafish bulbus arteriosus and the smooth muscle component of the chick cardiac outflow tract may be specifically labeled by DAF-2DA. Using this fluorescent dye they could distinguish the zebrafish bulbus arteriosus from "true" cardiac chambers, the atrium and ventricle (Grimes AC, Stadt HA, Shepherd IT, Kirby ML. Solving an enigma: arterial pole development in the zebrafish heart. Dev Biol 2006 Feb 15;290(2):265−76). The authors regret not including this information in the original version of their article.
Effects of tributyltin(IV) chloride exposure on early embryonic stages ofCiona intestinalis:In vivo and ultrastructural investigations
1993
The effects of tributyltin(IV) chloride (TBT chloride) solutions on ascidian embryos of Ciona intestinalis have been tested at different stages of development. It has been observed, in vivo, that TBT chooride inhibited cleavage of fertilized eggs and of embryo blastomeres giving rise to cellular masses that are not delimited by plasma membrane. Electron-dense precipitates of TBT chloride, probably as inorganic tin, have been observed by transmission electron microscopy in the egg cytoplasm of cellular masses. The same type of precipitate was present also inside the mitochondria, whose structure appeared to be highly modified. These ultrastructure aspects are indicative of a degenerative pro…
Courtship song and immune function in the field cricket Gryllus bimaculatus
2003
It has been assumed that sexual ornaments have evolved to reveal males’ health and vigour for females. Choosy females may indirectly use ornaments as an indicator of the presence and effectiveness of genes for resistance against parasites. In this study we tested whether females of the Mediterranean field cricket, Gryllus bimaculatus, can use courtship song as a cue for choosing males with high immunocompetence, measured as encapsulation rate of nylon implants and lytic activity of haemolymph. We found that female crickets preferred courtship songs from males with a high encapsulation rate. Female crickets also had a tendency to prefer courtship songs with high tick rate and long high-frequ…
Acetylcholinesterase activity in juvenileCiona intestinalis(Ascidiacea, Urochordata) after exposure to tributyltin
2012
The acetylcholinesterase (AChE) activity has been studied in 4-day post-fertilization juveniles of Ciona intestinalis exposed to tributyltin (TBT) at 10-5 M using the histochemical method of Karnovsky and Roots. Relative to vertebrate tissues and organs, the development of adult form of ascidians is interesting, because the analysis of many nuclear genes indicated that the ascidians are the closest living relatives of the vertebrates. Therefore, toxicity research using different approaches could provide data for comparative studies with vertebrates. AChE is over-expressed under chemical stress and in some diseases of vertebrates. Therefore, AChE is considered a biomarker of environmental co…
Casein kinase 2 inhibits HomolD-directed transcription by Rrn7 in Schizosaccharomyces pombe.
2014
In Schizosaccharomyces pombe, ribosomal protein gene (RPG) promoters contain a TATA analogue element called the HomolD box. The HomolD-binding protein Rrn7 forms a complex with the RNA polymerase II machinery. Despite the importance of ribosome biogenesis to cell survival, the mechanisms involved in the regulation of transcription of eukaryotic RPGs are unknown. In this study, we identified Rrn7 as a new substrate of the pleiotropic casein kinase 2 (CK2), which is a regulator of basal transcription. Recombinant Rrn7 from S. pombe, which is often used as a model organism for studying eukaryotic transcription, interacted with CK2 in vitro and in vivo. Furthermore, CK2-mediated phosphorylation…