Action of Combinations of Light And Electric Current On Planaria

The physiological investigation of invertebrates is important for the study of the evolution of functions, and also for understanding the laws of interaction of functions and living structures in an elementary form. Flatworms (planaria) attract special attention because of the simple organization of their nervous system, which at the same time possesses the basic features of a centralized system in the form of cephalization and synaptic transmission.     

Evaluation of the genotoxicity of some natural food colours using bacterial assays

The genotoxicity of 5 natural food colours currently permitted within the European Economic Community has been studied. Ability to induce DNA damage was investigated by the use of a recently-developed E. coli rec assay. The induction of reverse mutations in E. coli WP2 trp uvrA and S. typhimurium TA1538 his rfa uvrB was detected in fluctuation assays. Both types of assays were conducted with and without metabolic activation using caecal extracts and liver microsomes from rats.Results obtained in these systems suggest that none of the colourings screened induced detectable genotoxicity.     

The food of Planaria torva (Müller) (Turbellaria-Tricladida), a laboratory and field study

The food of Planaria torva was examined in the laboratory by exposing a range of potential prey to the triclad and observing prey mortality. Under these conditions P. torva fed mainly upon tubificid oligochaetes and gastropods. The former activity was regarded as untypical of the field situation and due to limitations of the laboratory habitat. The food of P. torva was determined in the field by taking monthly samples from October 1967 to May 1969 of a population living in Linlithgow Loch, West Lothian, Scotland. A serological technique was used to examine the gut contents of the field triclads. For reasons explained in the text, the prey organisms tested for serologically were gastropods, oligochaetes (Tubificidae), Asellus and chironomid larvae. Planaria torva fed most extensively on Gastropoda, Asellus was the second main food while Tubificidae and Chironomidae were taken only seasonally and in small numbers. The limited extent of feeding on tubificids supports the laboratory data. Small P. torva gave proportionately fewer positive reactions to the prey antisera than large individuals. This was explained by the fact that small individuals occurred most frequently in the warmer months and took smaller meals; both of these features shorten the detection period of food in the gut and therefore give fewer reactions. The diet of small and large P. torva was similar in the field and showed considerable overlap with that of Dugesia polychroa. The food of Polycelis tenuis, Dendrocoelum lacteum and Dugesia polychroa in Linlithgow Loch was described on an annual basis and the results confirmed earlier observations.     

Action of Arthrobacter ureafaciens inulinase II on several oligofructans and bacterial levans.

1. Arthrobacter ureafaciens inulinase II which converts inulin to di-D-fructofuranose 1,2' : 2,3' dianhydride (difructose anhydride III) leaving a small amount of oligosaccharides, was investigated in order to characterize its mode of action. 2. After the enzymatic reaction on the glucose-terminated inulin molecules had been completed, the oligosaccharides left in the enzyme digest were isolated, and identified to be the fructose-glucose oligosaccharides; O-beta-D-fructofuranosyl-(2 leads to 1)-O-beta-D-fructofuranosyl alpha-D-glucopyranoside (1-kestose), O-beta-D-fructofuranosyl-[(2 leads to 1)-O-beta-D-fructofuranosyl]2 alpha-D-glucopyranoside and O-beta-D-fructofuranosyl-[(2 leads to 1)-O-beta-D-fructofuranosyl]3 alpha-D-glucopyranoside. The difructose anhydride formation from the three fructose-glucose oligosaccharides in the separate reaction system with an increased substrate concentration was observed only with the latter two substrates, but not with the first one. 3. The difructose anhydride formation with several (2 leads to 1)-beta-linked fructose oligosaccharides and bacterial (2 leads to 6)-beta-fructans was examined. The (2 leads to 1)-beta-linked fructose oligosaccharides were effective as substrates for the enzyme with the exception of inulobiose, but the (2 leads to 6)-beta-fructans remained unaffected. 4. It was concluded that the enzyme attacks (2 leads to 1)-beta-linked fructan molecules from the nonreducing fructose ends and requires the presence of at least two adjacent (2 leads to 1)-beta-fructofuranosyl linkages.     

Cauliflower somatic embryogenesis and analysis of regenerant stability by ISSRs

  To study the somatic embryogenesis of Brassica oleracea var. botrytis L., hypocotyls were placed on Murashige and Skoog's medium (1962) with 1 mg.l^–1 of 2,4-dichlorophenoxyacetic acid and 1 mg.l^–1 of kinetin to induce callogenesis. After transfer of the calli to the maturation medium, somatic embryos appeared. They developed into plantlets and the potential of regeneration of the calli was maintained for more than 8 months. Thirty-five plantlets were produced after 2 months of culture, then transplanted into soil. Inter-simple sequence repeat markers generated by trinucleotidic and tetranucleotidic primers were tested for their ability to characterise genomic variations in the obtained plants. The absence of polymorphism between different regenerants from the same cultivar indicates the conformity of the regeneration protocol. Received: 4 February 2000 / Revision received: 22 May 2000 / Accepted: 23 May 2000     

5-n-alkylresorcinols of whole grain cereals and whole grain cereal products as biomarkers of healthy food

Epidemiological studies suggest that consumption of whole grain cereals and whole grain cereal products have many benefical health effects, including reducing risk of diabetes, obesity, coronary heart diseases, stroke and even some cancers. Precise knowledge protective compounds present in cereal grains can be achieved only when specific biomarkers (biological marker, indicator), that could provide estimation of grain cereals absorption and intake, are established and determined. 5-n-alkylresorcinols (main fraction of phenolic compounds in cereals), because of their specific occurrence only in bran fraction, obtained in refining of milling fractions process, could be a very good candidate to play the role of biomarker of whole grain intake. They are absorbed by animals and humans, present in human plasma and as metabolites in urine. Because composition of saturated homologues of 5-n-alkylresorcinols is different in rye and wheat grains, they could be used as an indicator of the intake of the specific type of cereals and whole grain cereal products.     

Fixation and Staining of Planaria for Histological Study

Fixation and staining of planaria can affect the interpretation of histopathological changes following their exposure to various agents. We assessed several fixation protocols with various stains in planaria to determine an optimal combination. Planaria were fixed in each of the following: 10% neutral buffered formalin, 2.5%, glutaraldehyde, Bouin's, Zenker's, 70% ethanol, and relaxant. In addition, planaria were fixed in relaxant and postfixed in each of the fixatives above. Paraffin embedded sections from each fixation protocol were stained with hematoxylin and eosin (H & E), toluidine blue, periodic acid-Schiff (PAS), or phosphotungstic acld-hematoxylin (PTAH). Relaxant fixed planaria were also stained with Steiner's, Holmes, trichrome, Giemsa, Grocott's methenamine silver (GMS) and antibodies for intermediate filaments (cytokeratin, vimentin and desmin). Relaxant and Zenker's gave the best fixation with minimal artifacts. Formalin, glutaraldehyde, and ethanol were unacceptable because they caused contortions of the body, crenation, and a darkly pigmented epidermis. Gastroderm could be differentiated from stroma best when stained with H & E, toluidine blue and PTAH. Other organ systems differentially stained included the epidermis, marginal adhesion gland, nervous tissue, and muscle. PAS, Steiner's, Holmes, trichrome and the intermediate filament stains were not useful for planaria staining. The most morphological information was obtained with relaxant fixative and a combination of sections stained with H & E and PTAH.     

Mineral concentrations in whole mice and rats used as food

Calcium (Ca), magnesium (Mg), copper (Cu), iron (Fe), manganese (MD), and zinc (Zn) concentrations were measured in whole mice (five sizes) and rats (six sizes). Ca concentrations increased with age in both mice (1.2–2.3%) and rats (1.9–3.3%). Mg levels ranged from 0.09 to 0.13% (mice) and from 0.11 to 0.18% (rats), with the medium-size class of both species having the highest values. Cu (7.9–19.2 and 10.8–60.6 mg/kg) and Zn (58.0–82.5 and 73.2–113.6 mg/kg) generally decreased with age in both species, while Mn levels tended to increase with age (0.2–13.1 mg/kg, mice; 6.2–28.3 mg/kg, rats). Fe values were highest in neonates and adult size classes, ranging from 113.4 to 181.3 mg/kg (mice) and 111.3 to 332.6 mg/kg (rats). Rats usually contained higher concentrations of individual minerals than equivalent age categories of mice, even though both were fed identical diets. All rodents analyzed generally met known dietary requirements of mammalian carnivores, but differences between mice and rats were apparent. Specific mineral nutrient requirements for carnivorous birds and reptiles have not been determined. © 1996 Wiley-Liss, Inc.