Growth and mineral nutrition of two Chlorococcalean algae

The effect of composition of the medium and pH on the growth of Pediastrum duplex Meyen and Dictyosphaerium pulchellum Wood was studied. Both species showed preference to alkaline conditions. The ammonium nitrate grown colonies of D. pulchellum lacked mucilage and showed a more compact form, resembling D. pulchellum var. minitum Deflandre. From this it appears that D. pulchellum var. minitum is a nutritional variant of the species and not a stable variety.     

Effets à long terme de 4 détersifs chez le pulmoné d'eau douce Lymnaea stagnalis L.: Intoxication des adultes

Detergents added to the rearing water of the molluscLymnaea induce a sharp mortality of all the animals of each experimental group after a variable delay, depending upon the nature of the detergent and its concentration.No important perturbation of the shell growth is noted with the cationic detergent; conversely a light decrease is observed with the anionic detergents and a very severe effect is induced by a commercial washing mixture.The fecundity is always reduced by the detergents: the number of egg-masses per snail and the number of eggs per mass are diversely changed according to the products.In many cases the egg fertility is decreased and the duration of embryogenesis is increased. For each detergent the reduction of the biological yield ofLymnaea is calculated and the curves drawn allow to classify these detergents according to their chemical nature: among the anionic detergents, A has a low toxicity, B and P are characterized by higher toxicities and the cationic detergent is strongly toxic.

     

Effects of eyestalk ablation on growth and food conversion efficiency of the freshwater prawn Macrobrachium lanchesteri (de Man)

Bilateral eyestalk ablation in the freshwater prawn Macrobrachium lanchesteri results in high mortality, while unilateral eyestalk ablated prawns exhibited a high survival rate. There was marked increase in the growth of bilateral eyestalk-ablated prawns (47.70 mg/prawn) as compared to those that were unilaterally ablated (19.19 mg/prawn).     

Effets du rubidium et du césium sur la croissance et la nutrition minerale des characees

Résumé Le rubidium et le césium introduits à l'état de chlorure dans le milieu de culture ont à faible dose un effet stimulant sur la croissance de Chara fragilis et de Chara vulgaris. La résistance de ces végétaux à l'action toxique des deux ions est accrue par l'addition de potassium au milieu.Les analyses chimiques confirment que le rubidium et le césium sont antagonistes vis-à-vis du potassium et du sodium alors qu'ils ne modifient pas de manière significative le taux de calcium.

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Chara fragilis and Chara vulgaris were cultivated in a natural medium containing rubidium and caesium as chloride.The growth of Characeae was increased after culture in the solutions containing Rb and Cs in small amount. The resistance to the toxic effects of these two ions is enhanced if potassium chloride is added to the medium.Quantitative analyses indicate that Rb and Cs decrease the rate of Na and K but have no significative influence on the rate of Ca.

Université de Dijon, Laboratoire de Nutrition minérale des Végétaux     

Alloxan: A growth accelerator for a nitrogen-fixing blue-green alga

Effect of Alloxan was studied on a nitrogen-fixing blue-green alga: Westiellopsis prolifica in pure cultures. Concentrations of Alloxan, 10 g to 50 g/ml stimulate the growth of the alga and increase the chlorophyll, carotin and phycocyanin content of the cultures.     

The segregation of lambs into ‘responders’ and ‘non-responders’: Response to vaccination with irradiated Trichostrongylus colubriformis larvae before weaning

Random bred Merino ram and ewe lambs were vaccinated at 1, 2 and/or 3 months of age with irradiated T. colubriformis larvae. An exponentially increasing challenge of normal larvae was given to all groups including unvaccinated controls commencing at 1 month of age. The results, based on faecal egg counts, showed a dissociation into animals which responded to vaccination (geometric mean egg count 441) and those which did not (geometric mean egg count 1567). The proportion of responders was greatest in groups first vaccinated at the earliest age (1 month). Wool growth and liveweight gains showed severe depression corresponding to peak egg counts, however, responders were less affected than non-responders. There was no correlation between haemoglobin type and resistance to challenge. Faecal egg counts after impulse challenge with 10,000 normal larvae given at about 6$\text{1}\text{2}$ months of age showed a significant ranked correlation with those obtained during the primary exponential challenge. These results confirm that a proportion of young lambs respond to vaccination with irradiated larvae, and that genetically-determined factors are implicated in the ability of animals to respond to vaccination at an early age.     

Age- and density-dependent growth within populations of the ectoparasitic digenean Transversotrema patialense on the fish host

Mills C. A. 1980. Age- and density-dependent growth within populations of the ectoparasitic digenean Transversotrema patialense on the fish host. Internationaljournal for Parasitology, 10: 287–291. Growth of the adult ectoparasitic digenean Transversotrema patialense on the fish host Brachydanio rerio is shown to be age-dependent, ceasing 15–20 days post infection. The vitelline glands expand greatly in size after infection from 1.25 % of cercarial area to 20.7 % of that of the mature adult. There is an increase in the occurrence of reproductive abnormalities in old parasites but this alone fails to account for the decline in egg production found as populations of T. patialense age. Growth of adult T. patialense is density-dependent with reduced growth at high initial parasite densities per host.     

Chemically defined media for growth and sporulation of Entomophthora virulenta

Amino acids, salts, and vitamins were combined with dextrose to test their effect on growth and sporulation of Entomophthora virulenta in liquid shake culture. The addition of a vitamin solution to the tested media did not enhance growth or sporulation. MgSO₄·7H₂O was the only salt individually tested that allowed for good growth and sporulation. MgSO₄·7H₂O concentrations exceeding 250 mg/liter in media lacking other salts inhibited sporulation. A simple medium of l-arginine, l-leucine, glycine, and mineral salts allowed high growth and sporulation.     

Demonstration of growth in porcine thyroid cell culture

Eagle's minimum essential medium supplemented with 20 per cent newborn calf serum (N.C.S.) allows porcine thyroid cell survival but not cell growth in vitro. In NCTC 109 medium supplemented with 20 per cent N.C.S. these cells actively grow and may be serially propagated. Cell population doubling time expressed as DNA doubling value is 3.5 days at 37 degrees C in 95 per cent air-5 per cent CO2. Thyrotropin does not affect porcine thyroid cell multiplication in vitro but stimulates the plating efficiency in primary cultures to about 130 per cent of controls. Cell selection was obtained by replacing media with Earle's balanced salt solution. This operation provoked death of nearly all cells by day 18 but subsequent addition of growth medium resulted in proliferation of epithelial cell clones. From generation 2 to generation 8, cells produce thyroglobulin but they do not actively trap iodide nor form follicles when thyrotropin is added to the media. Cell selection, demonstration of growth, as well as freeze-storage techniques described in this paper permit selection and storage of porcine thyroid cells and the potential constitution of cell collections.     

Chemoautotrophic growth of Rhodopseudomonas species with hydrogen and chemotrophic utilization of methanol and formate

A chemolithoautotrophic type of metabolism, which was hitherto unknown for purple nonsulfur bacteria, was demonstrated by growth experiments using Rhodopseudomonas capsulata Kb1 and Rhodopseudomonas acidophila 10050. These strains were able to grow in a mineral medium in the dark at the expense of H₂, O₂, and CO₂. A minimum doubling time of 9 h was obtained for R. capsulata under an atmosphere containing less than 15% oxygen; higher oxygen concentrations suppressed autotrophic but not chemoorganotrophic growth. Oxygen sensitivity of chemoautotrophically growing cells of R. acidophila was even more pronounced, whereas cells growing chemotrophically on methanol almost tolerated the oxygen concentration of air. Highest oxygen sensitivity of growth of R. acidophila was observed with formate as substrate. The growth yield of cultures grown semiaerobically in the dark on methanol was 0.23 g dry cell material per g methanol consumed.