Search results for "Actinopterygii"
showing 10 items of 210 documents
Traditional and experimental floating fish aggregating devices in the Gulf of Castellammare (NW Sicily): Results from catches and visual observations
1999
Floating fish aggregating devices (FADs) have long been used to attract fish in NW Sicily since antiquity. Recently, a number of changes have been made to the type of material employed to construct FADs, with the aim of increasing their effectiveness. In this paper we compare the catches made at eight experimental floating FADs (polypropylene ropes frayed at the ends) with those obtained at eight traditional FADs in the Gulf of Castellammare. A total of 672 samples were collected during summer and autumn in 1995 and 1996 at the 16 FADs using a surrounding net. Visual observations of fishes associated with the FADs were also conducted to obtain qualitative information about the spatial distr…
Effects of lindane on fish carbohydrate metabolism.
1991
Exposure of the European eel (Anguilla anguilla) to a high sublethal concentration of 0.335 ppm (0.50 of the 96-hr LC50) of lindane for 6, 12, 24, 48, 72, and 96 hr affected carbohydrate metabolism. Muscle glycogen levels decreased significantly (P less than 0.05) at 6, 12, 24, 48, 72, and 96 hr; liver glycogen content did not decline at any time. Muscle glucose levels in fish were elevated at 6, 12, 24, 48, 72, and 96 hr but in liver, the levels increased only at 96 hr. Mean values of muscle and liver pyruvate were elevated significantly (P less than 0.05) at 6, 12, 24, 48, and 72 hr. Muscle lactate levels increased at 6, 12, 24, and 48 hr in pesticide-treated fish. Liver lactate levels we…
Lindane-induced changes in carbohydrate metabolism in Anguilla anguilla
1992
Abstract 1. Anguilla anguilla (L.) was exposed to a sublethal concentration of 0.167 ppm (0.25 of the 96-hr lc 50 ) of lindane for 6, 12, 24, 48, 72 and 96 hr. 2. Changes in glycogen, glucose, pyruvate and lactate contents of liver and muscle after lindane exposure, were studied. 3. Muscle and liver glycogen levels decreased significantly during the exposure time. Muscle glucose values increased but on the other hand we found a decrease in those of liver. 4. Muscle and liver pyruvate content increased as did lactate levels in both tissues. 5. The observed effects of lindane on carbohydrate metabolism in fish are discussed in relation to acute stress syndrome.
A peek inside the neurosecretory brain throughOrthopedialenses
2008
The wealth of expression and functional data presented in this overview discloses the homeogene Orthopedia (Otp) as critical for the development of the hypothalamic neuroendocrine system of vertebrates. Specifically, the results depict the up-to-date portrait of the regulation and functions of Otp. The development of neuroendocrine nuclei relies on Otp from fish to mammals, as demonstrated for several peptide and hormone releasing neurons. Additionally, the activity of Otp is essential for the induction of the dopaminergic phenotype in the hypothalamus of vertebrates. Recent insights into the pathways required for Otp regulation have revealed the implication of the main extracellular signal…
Fluorescent in situ hybridization (FISH): A useful diagnostic tool for childhood conjunctival melanoma
2021
Introduction: Conjunctival melanoma is extremely rare in children and has low rates of resolution. Definitive histopathological diagnosis based exclusively on microscopic findings is sometimes difficult. Thus, early diagnosis and adequate treatment are essential to improve clinical outcomes. Clinical case: We present the first case in which the fluorescent in situ hybridization (FISH) diagnostic technique was applied to a 10-year-old boy initially suspected of having amelanotic nevi in his right eye. Based on the 65% of tumor cells with 11q13 (CCND1) copy number gain and 33% with 6p25 (RREB1) gain as measured by the FISH analysis, and on supporting histopathological findings, the diagnosis …
Physiological problems of teleost ambisexuality
1988
The normal occurrence of spontaneous sex inversion among teleosts is a recent item within current concepts on vertebrate reproductive physiology. Investigations on the subject are mostly descriptive and deal with morphological and behavioral aspects. The concept of social control of sex inversion has been received with great interest. However, research on physiological processes that take place inside a fish when it changes sex must be rated as fragmentary. Steroid hormones are supposed to play a major role in sex inversion. But a cause and effect relationship has not yet been established. More experimental studies on more types of ambisexual species are badly needed. Future work will show …
Social control of testicular steroidogenic capacities in the Siamese fighting fishBetta splendens Regan
1987
Male Siamese fighting fish (Betta splendens Regan) of the veiltail variety were raised. At the age of 4 ½ months they were either isolated or community-housed for 2 ½ months. After that time the relative fin lengths were determined, and the in vitro metabolism of testosterone by the testes of the fishes was investigated. Community-housed specimens had shorter fins than the isolated males. Their testes formed less 11-oxy- and more 5β-steroids than those of the isolated males. This difference was even larger when high- and low-ranking community-based specimens were compared. The appearance of low-ranking males resembled that of females, and the main products of their testes were 5β-reduced st…
Androgen metabolism in the skin of the rainbow trout (Oncorhynchus mykiss)
1993
Pieces of skin of male and female rainbow trout (Oncorhynchus mykiss) were incubated with testosterone and 11-ketotestosterone as substrates. In immature fish the conversion rate was low. In non-spawning adult males 11-ketotestosterone was reduced to 5α-11KDHT (up to 5.2%). In the fish in spawning condition the 5α-reduction rate was only about 1 to 2%. In the same specimens incubated with testosterone a high 11β-hydroxylase activity (23.8-25% in the male and 13% in the female skin) was found. Similar sex specific differences were observed for the occurence of 5α-reduced metabolites (about 20% in the male and 13% in the female tissue).
Sex and sexual ornamentation associated with survival of the cyprinid fish, Rutilus rutilus, under disease stress
2013
By conveying information of disease resistance, sexual signals may be used as cues for adaptive mate choice. Here we report observations on survival of laboratory-maintained, wild-collected, sexually mature, ready-to-spawn cyprinid fish, Rutilus rutilus (roach), under accidental epidemic attributed to Flavobacterium psychrophilum, diagnosed using species-specific PCR. The fish were maintained in a single tank. During the 27 days observation period, both the proportion of fish surviving the infection as well as the length-adjusted mean survival time of the fish that died was the highest among the high-ornamented males with large breeding tubercles, intermediary among the low-ornamented males…
Rearing background and exposure environment together explain higher survival of aquaculture fish during a bacterial outbreak
2019
1.Parasitic diseases represent one of the greatest challenges for aquaculture worldwide and there is an increasing emphasis on ecological solutions to prevent infections. One proposed solution is enriched rearing, where traditional stimulus‐poor rearing tanks are equipped with different types of structures to increase habitat complexity. Such spatial enrichment is known to increase survival of fish during parasite epidemics, but the underlying mechanisms are still unclear. 2.We studied whether enriched rearing affected infection of an important fish pathogen Flavobacterium columnare in young Atlantic salmon (Salmo salar) and sea‐migrating brown trout (Salmo trutta). First, we used natural b…