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Different Feeding Habits (different + feeding_habit)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

The role of biomarkers to assess oil-contaminated sediment quality using toxicity tests with clams and crabs,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2008
Carmen Morales-Caselles
Abstract A 28-d bioassay was conducted with two invertebrate species with different feeding habits, the clam Ruditapes philippinarum and the shore crab Carcinus maenas. The purpose of the present study was to assess the quality of sediments affected by oil spills in different areas of the Spanish coast. The organisms were exposed to environmental samples of oil-contaminated sediments during four weeks and, after the experiment, a suite of biomarkers of exposure was measured: The phase one detoxification system was assessed by ethoxyresorufin- O -deethylase (EROD) activity; glutathione- S -transferase (GST) is a phase-two detoxification enzyme but also is implicated in oxidative stress events; glutathione peroxidase (GPX), glutathione reductase (GR), and the ferric reducing ability of plasma (FRAP) assay were analyzed to determine the antioxidant activity of the tissues. The biomarker results were correlated with the chemical compounds bound to sediments (polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], Zn, Cd, Pb, Cu, Ni, Co, V) and a principal component analysis was carried out with the purpose of linking all the variables and to detect those contaminated sediments potentially harmful to the biota. Results showed induction of biomarkers in both invertebrate species and significant differences (p < 0.05; p < 0.01) were established among sediments affected by different spills. The use of the selected biomarkers together with the sediment chemical analysis assesses the bioavailability of contaminants and has proven to be a suitable tool to monitor the environmental quality of sediments affected by oil spills. [source]

Digestive enzyme spectra in crustacean decapods (Paleomonidae, Portunidae and Penaeidae) feeding in the natural habitat

AQUACULTURE RESEARCH, Issue 3 2009
Maria Santos Reis Bonorino Figueiredo
Abstract This work describes the profile of five proteases and four carbohydrases from the crustacean decapods Macrobrachium australiense (Holthuis), Scylla serrata (Forskal), Portunus pelagicus (Linnaeus), Penaeus esculentus, Penaeus plebejus (Hess) and Metapenaeus bennettae (Racck & Dall), feeding in the natural habitat, in order to provide an indication of their digestive capabilities. The results raised the following points. First, species from each family showed a particular suite of digestive enzymes. Second, the activity of cellulase from M. australiensis and S. serrata, using AZCL-HE cellulose as the substrate, was around 90% higher than that observed with AZO-CM cellulose. However, for P. pelagicus and P. esculentus, the enzyme activity was better with AZO-CM cellulose. Third, M. australiense displayed the highest ratio of amylase to protease activity. In contrast, Portunidae species, P. pelagicus and S. serrata showed the lowest ratios. Fourth, comparison of the laminarinase activity of M. bennettae and P. esculentus in October (Spring) and December (early Summer) showed a significant decrease in December. Finally, the wide distribution of digestive enzymes in these crustaceans may reflect different feeding habits and habitats. [source]

Phytase-producing bacteria in the digestive tracts of some freshwater fish

AQUACULTURE RESEARCH, Issue 3 2009
Tanami Roy
Abstract Isolation and enumeration of phytase-producing bacterial flora in the foregut and hindgut regions of the gastrointestinal tracts of 10 culturable freshwater teleosts of different feeding habits, namely rohu (Labeo rohita), catla (Catla catla), mrigal (Cirrhinus mrigala), bata (Labeo bata), kalbasu (Labeo calbasu), Nile tilapia (Oreochromis niloticus), climbing perch (Anabas testudineus), common carp (Cyprinus carpio), silver carp (Hypophthalmichthys molitrix) and grass carp (Ctenopharyngodon idella), have been carried out. Microbial culture of the gut mucosa on selected nutrient media following the enrichment culture technique was performed for bacterial isolation. The bacterial isolates were screened on the basis of their enzyme-producing ability. The bacterial population on the tryptone soya agar (TSA) plate was maximum in the hindgut region of bata, followed by mrigal and minimum in the foregut region of Nile tilapia. In modified phytase screening medium (MPSM), phytase-producing strains were recorded at higher densities in the foregut region of mrigal and grass carp and minimum in the foregut region of bata. In case of the hindgut, maximum phytase-producing strains were present in grass carp and mrigal and minimum in rohu. In general, in MPSM, the bacterial population was lower in the hindgut region of all the 10 species of fish examined. The phytase-producing ability of the selected 31 strains (16 from the foregut and 15 from the hindgut region) was determined by clearing zones on phytate-containing plates. Among these isolates, 22 strains (12 from the foregut and 10 from the hindgut region) were selected as potent phytase producers according to a quantitative enzyme assay. The highest phytase activity was observed in the bacterial strains LF1 and LH1 isolated from the fore and the hindgut regions of rohu respectively. Both the strains were identified as Bacillus licheniformis on the basis of phenotypic characteristics as well as 16S rDNA sequence analysis. [source]

Mandible morphology, dental microwear, and diet of the extinct giant rats Canariomys (Rodentia: Murinae) of the Canary Islands (Spain)

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2010
CYRIL FIRMAT
An ecomorphological approach of mandible shape through Fourier analyses combined with a paleodietary analysis of dental microwear patterns is used to reconstruct the diet of the extinct endemic Canariomys bravoi Crusafont, Pairó & Petter, 1964 and Canariomys tamarani López-Martínez & López-Jurado, 1987. These two large rodents, respectively, lived on Tenerife and Gran Canaria, the central islands of the Canarian Archipelago. Mandible shape and dental microwear respectively inform us on the volume of vegetal matter and on the presence of grass in the diet. Both Canariomys, which are of similar size, possess relatively similar mandible outlines and microwear patterns. For each species, a diet based on plant materials except grass is the most likely. Such results chime with the similar environments offered by the islands in which the species lived. On the contrary, molar morphology suggests different feeding habits of the two Canariomys. Thus, this suggests a case of mosaic evolution between teeth and mandibles, as well as the likely sensitivity of mandible shape to a combination of ecological and allometric factors. These new data obtained from the fossil record underline the propensity of island endemic mammals to yield surprising examples of phenotypic evolution. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 28,40. [source]