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At least 235 records · Page 13Linked to original sources
PubMed1991

GATA repeats in the genome of Asellus aquaticus (Crustacea, Isopoda).

A 500 bp fragment of Drosophila genomic DNA containing 37 copies of the tetranucleotide GATA was used to probe, by Southern DNA blotting and in situ hybridization, two natural populations of the isopod crustacean Asellus aquaticus collected from the Sarno and Tiber rivers. This species does not have a recognizable sex chromosome pair. In a number of males from the Sarno population chromomycin A3 staining reveals a heteromorphic chromosome pair. The heterochromosome has two blocks of heterochromatin. After digestion of genomic DNA with six restriction endonucleases and hybridization with the GATA probe, the two populations exhibit different fragment length patterns. No sex-linked pattern was observed in either population. In situ hybridization to chromosomes of males and females from the Sarno population does not reveal any sex-specific pattern of labelling and indicates a scattered distribution of GATA sequences on most chromosomes with some areas of preferential concentration. The heterochromatic areas of the male heterochromosome are not labelled.

Animals↗
PubMed1977

[Influence of cymothoidae (Crustacea, Isopoda, Flabellifera) on some hematological constants of the host-fishes (author's transl)].

Some hematological constants (number of erythrocytes--hemaglobin rate--hematocrit--mean blood corpuscule volume--mean corpuscular hemoglobin concentration--mean corpuscular hemoglobin) are studied in non-parasitized and parasitized Teleost fishes (parasites are Cymothoid Isopods). The parasitized fishes show an anaemia, resulting from a decreasing number of erythrocytes in circulation. The spleen undergoes a hypertrophy and a hypervascularization.

Animals↗
PubMed1988

Unusual basement layer in the midgut of gammaridean Niphargus virei Chevreux (Crustacea, Amphipoda).

The basement membrane of the midgut and posterior caeca epithelium in the gammaridean amphipod Niphargus virei Chevreux, 1896 is made of an unusual structure. This basal lamina, properly called "basal layer", shows a dense sheet formed by a system of dense hexagonal plates connected by thin filaments. Histochemical studies and enzymatic reactions lead to the conclusion that these structures are proteinaceous, without collagenous protein, and embedded in a neutral polysaccharide matrix. The possible mechanical significance of these mesenteric structures is discussed.

Animals↗
PubMed1979

[Influence of the cymothoid isopods Meinertia oestroides, Meinertia parallela, and Anilocra physodes (Crustacea; parasites of fish) on the growth of hosts, Boops boops and Pagellus erythrinus (Sparidae) (author's transl)].

Studies of weight-size (W = aLb) and growth (L = aT + b) in fish (Boops boops and Pagellus erythrinus), potential hosts of some Cymothoid isopods (Meinertia oestroides, Meinertia parallela, and Anilocra physodes) have been performed. Infested fishes show a slight decrease in weight compared to normal fish. Cymothoid do not exert a significant influence on the weight-size ratio; on the other hand, a delay in growth does occur.

Animals↗
PubMed1991

Toxicity of four common pollutants to the freshwater macroinvertebrates Chironomus riparius Meigen (Insecta:Diptera) and Gammarus pulex (L.) (Crustacea: Amphipoda).

The lethal toxicities of the four pollutants 3,4-dichloroaniline (DCA), atrazine, copper, and lindane were determined for the 2nd larval instar of the insect Chironomus riparius Meigen and the juvenile stage (2nd or 3rd moult) of the crustacean Gammarus pulex (L.). Median lethal concentrations (LC50s) were determined over a 240 h test period. The order of toxicity of the test chemicals is different for each species. For C. riparius, lindane was the most toxic, followed by copper, DCA, and atrazine. During the first 96 h of exposure, the order for G. pulex was copper, lindane, then DCA and atrazine with similar LC50 values. However, at 240 h lindane replaced copper as the most toxic chemical to G. pulex. The relative sensitivity of the two species was dependent on both the toxicant and the exposure period. The lethal concentrations determined for the four chemicals are compared to the results of other toxicity studies and discussed with respect to current standard test methods.

Aniline Compounds↗
PubMed1993

New model systems for studying the evolutionary biology of aging: crustacea.

Progress in any area of biology has generally required work on a variety of organisms. This is true because particular species often have characteristics that make them especially useful for addressing specific questions. Recent progress in studying the evolutionary biology of senescence has been made through the use of new species, such as Caenorhabditis elegans and Drosophila melanogaster, because of the ease of working with them in the laboratory and because investigators have used theories for the evolution of aging as a basis for discovering the underlying mechanisms. I describe ways of finding new model systems for studying the evolutionary mechanisms of aging by combining the predictions of theory with existing information about the natural history of organisms that are well-suited to laboratory studies. Properties that make organisms favorable for laboratory studies include having a short generation time, high fecundity, small body size, and being easily cultured in a laboratory environment. It is also desirable to begin with natural populations that differ in their rate of aging. I present three scenarios and four groups of organisms which fulfill these requirements. The first two scenarios apply to well-documented differences in age/size specific predation among populations of guppies and microcrustacea. The third is differences among populations of fairy shrimp (Anostraca) in habitat permanence. In all cases, there is an environmental factor that is likely to select for changes in the life history, including aging, plus a target organism which is well-suited for laboratory studies of aging.

Aging↗